Investigators '90 percent sure' of bomb on crashed Russian plane

Before you go, we thought you'd like these...
Russia Asks FBI to Join Investigation Into Crashed Charter Flight

Investigators of the Russian plane crash in Egypt are "90 percent sure" the noise heard in the final second of a cockpit recording was an explosion caused by a bomb, a member of the investigation team told Reuters on Sunday.

READ MORE: Russia flies thousands of tourists from Egypt after crash

The Airbus (AIR.PA) A321 crashed 23 minutes after taking off from the Sharm al-Sheikh tourist resort eight days ago, killing all 224 passengers and crew. Islamic State militants fighting Egyptian security forces in Sinai said they brought it down.

"The indications and analysis so far of the sound on the black box indicate it was a bomb," said the Egyptian investigation team member, who asked not to be named due to sensitivities. "We are 90 percent sure it was a bomb."

Watch more coverage below:

Egypt Crash Committee: Noise Heard in Cockpit Recording from Russian Jet

His comments reflect a much greater degree of certainty about the cause of the crash than the investigation committee has so far declared in public.

Lead investigator Ayman al-Muqaddam announced on Saturday that the plane appeared to have broken up in mid-air while it was being flown on auto-pilot, and that a noise had been heard in the last second of the cockpit recording. But he said it was too soon to draw conclusions about why the plane crashed.

See more in the gallery below:

36 PHOTOS
Russian plane crash in Egypt wreckage and aftermath
See Gallery
Investigators '90 percent sure' of bomb on crashed Russian plane
In this photo made available Monday, Nov. 2, 2015, and provided by Russian Emergency Situations Ministry, Egyptian Military on cars approach a plane's tail at the wreckage of a passenger jet bound for St. Petersburg in Russia that crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Russian cargo plane on Monday brought the first bodies of Russian victims killed in a plane crash in Egypt home to St. Petersburg, a city awash in grief for its missing residents. (Maxim Grigoriev/Russian Ministry for Emergency Situations via AP)
In this Russian Emergency Situations Ministry photo, made available on Monday, Nov. 2, 2015, Russian Emergency Ministry experts work at the crash site of a Russian passenger plane bound for St. Petersburg in Russia that crashed in Hassana, Egypt's Sinai Peninsula, on Monday, Nov. 2, 2015. A Russian cargo plane on Monday brought the first bodies of Russian victims home to St. Petersburg, from Egypt.(Russian Ministry for Emergency Situations photo via AP)
In this Russian Emergency Situations Ministry photo, made available on Monday, Nov. 2, 2015 Egyptian soldiers collect personal belongings of plane crash victims at the crash site of a passenger plane bound for St. Petersburg in Russia that crashed in Hassana, Egypt's Sinai Peninsula, on Monday, Nov. 2, 2015. A Russian cargo plane on Monday brought the first bodies of Russian victims home to St. Petersburg, from Egypt.(Russian Ministry for Emergency Situations photo via AP)
In this Russian Emergency Situations Ministry photo, made available on Monday, Nov. 2, 2015, Russian Emergency Ministry experts work at the crash site of a Russian passenger plane bound for St. Petersburg in Russia that crashed in Hassana, Egypt's Sinai Peninsula, on Monday, Nov. 2, 2015. A Russian cargo plane on Monday brought the first bodies of Russian victims home to St. Petersburg, from Egypt.(Russian Ministry for Emergency Situations photo via AP)
Debris belonging to the A321 Russian airliner are seen at the site of the crash in Wadi el-Zolmat, a mountainous area in Egypt's Sinai Peninsula on November 1, 2015. International investigators began probing why a Russian airliner carrying 224 people crashed in Egypt's Sinai Peninsula, killing everyone on board, as rescue workers widened their search for missing victims. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
Debris of a Russian airplane is seen at the site a day after the passenger jet bound for St. Petersburg, Russia, crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Metrojet plane, bound for St. Petersburg in Russia, crashed 23 minutes after it took off from Egypt's Red Sea resort of Sharm el-Sheikh on Saturday morning. The 224 people on board, all Russian except for four Ukrainians and one Belarusian, died. (AP Photo)
In this photo made available Monday, Nov. 2, 2015, and provided by Russian Emergency Situations Ministry, Egyptian Military experts examine a piece of an engine at the wreckage of a passenger jet bound for St. Petersburg in Russia that crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Russian cargo plane on Monday brought the first bodies of Russian victims killed in a plane crash in Egypt home to St. Petersburg, a city awash in grief for its missing residents. (Maxim Grigoriev/Russian Ministry for Emergency Situations via AP)
A Russian investigator walks near wreckage a day after a passenger jet bound for St. Petersburg, Russia, crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Metrojet plane, bound for St. Petersburg in Russia, crashed 23 minutes after it took off from Egypt's Red Sea resort of Sharm el-Sheikh on Saturday morning. The 224 people on board, all Russian except for four Ukrainians and one Belarusian, died. (AP Photo/Amr Nabil)
A helicopter of the Egyptian security forces fly over the site a day after a passenger jet bound for St. Petersburg, Russia, crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Metrojet plane, bound for St. Petersburg in Russia, crashed 23 minutes after it took off from Egypt's Red Sea resort of Sharm el-Sheikh on Saturday morning. The 224 people on board, all Russian except for four Ukrainians and one Belarusian, died. (AP Photo)
In this photo taken Sunday, Nov. 1, 2015 and provided by Russian Ministry for Emergency Situations Monday, Nov. 2, Russian Emergency Situations Minister Vladimir Puchkov, left, talks with Russian Transport Minister Maxim Sokolov, fifth right, as they inspect the wreckage of a passenger jet bound for St. Petersburg in Russia that crashed in Hassana, Egypt. A Russian cargo plane on Monday brought the first bodies of Russian victims killed in the plane crash in Egypt home to St. Petersburg, a city awash in grief for its missing residents. (Maxim Grigoriev/Russian Ministry for Emergency Situations via AP)
In this photo made available Monday, Nov. 2, 2015, and provided by Russian Emergency Situations Ministry, Egyptian Military on cars approach a plane's tail at the wreckage of a passenger jet bound for St. Petersburg in Russia that crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Russian cargo plane on Monday brought the first bodies of Russian victims killed in a plane crash in Egypt home to St. Petersburg, a city awash in grief for its missing residents. (Maxim Grigoriev/Russian Ministry for Emergency Situations via AP)
SUEZ, EGYPT - NOVEMBER 01: A plane part is seen as the Egyptian officials inspect the crash site of Russian Airliner in Suez, Egypt on November 01, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on yesterday. According to Egypts Civil Aviation Authority, the plane had been lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Alaa El Kassas/Anadolu Agency/Getty Images)
Debris of the A321 Russian airliner lie on the ground a day after the plane crashed in Wadi al-Zolomat, a mountainous area in Egypt's Sinai Peninsula, on November 1, 2015. International investigators began probing why the Russian airliner carrying 224 people crashed in the Sinai Peninsula, killing everyone on board, as rescue workers widened their search for missing victims. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
Russian investigators stand near debris, luggage and personal effects of passengers a day after a passenger jet bound for St. Petersburg in Russia crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Metrojet plane crashed 23 minutes after it took off from Egypt's Red Sea resort of Sharm el-Sheikh on Saturday morning. The 224 people on board, all Russian except for four Ukrainians and one Belarusian, died. (AP Photo/Amr Nabil)
Debris of the A321 Russian airliner lie on the ground a day after the plane crashed in Wadi al-Zolomat, a mountainous area in Egypt's Sinai Peninsula, on November 1, 2015. International investigators began probing why the Russian airliner carrying 224 people crashed in the Sinai Peninsula, killing everyone on board, as rescue workers widened their search for missing victims. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
SUEZ, EGYPT - NOVEMBER 01: Egyptian officials inspect the crash site of Russian Airliner in Suez, Egypt on November 01, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on yesterday. According to Egypts Civil Aviation Authority, the plane had been lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Alaa El Kassas/Anadolu Agency/Getty Images)
SUEZ, EGYPT - NOVEMBER 01: Egyptian officials inspect the crash site of Russian Airliner in Suez, Egypt on November 01, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on yesterday. According to Egypts Civil Aviation Authority, the plane had been lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Alaa El Kassas/Anadolu Agency/Getty Images)
Members of the Egyptian security forces stand guard at the site a day after a passenger jet bound for St. Petersburg, Russia crashed in Hassana, Egypt, on Sunday, Nov. 1, 2015. The Metrojet plane, bound for St. Petersburg in Russia, crashed 23 minutes after it took off from Egypt's Red Sea resort of Sharm el-Sheikh on Saturday morning. The 224 people on board, all Russian except for four Ukrainians and one Belarusian, died. (AP Photo)
CAIRO, EGYPT - OCTOBER 31: Ambulances bring the bodies of the victims found at crash site of Russian Airliner, at Zinhoum Hospital's Morgue in Cairo, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Ibrahim Ramadan/Anadolu Agency/Getty Images)
CAIRO, EGYPT - OCTOBER 31: Ambulances bring the bodies of the victims found at crash site of Russian Airliner, at Zinhoum Hospital's Morgue in Cairo, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Ibrahim Ramadan/Anadolu Agency/Getty Images)
CAIRO, EGYPT - OCTOBER 31: Ambulances bring the bodies of the victims found at crash site of Russian Airliner, at Zinhoum Hospital's Morgue in Cairo, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Ibrahim Ramadan/Anadolu Agency/Getty Images)
CAIRO, EGYPT - OCTOBER 31: Ambulances bring the bodies of the victims found at crash site of Russian Airliner, at Zinhoum Hospital's Morgue in Cairo, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Ibrahim Ramadan/Anadolu Agency/Getty Images)
Egyptian ambulance arrives to Kabret military air base by the Suez Canal on October 31, 2015, after victims of a Russian airliner that crashed in the Sinai Peninsula were brought to the base before being transported to a morgue. Egypt's government said 15 bodies have been recovered and transferred to a morgue so far from the site of the crash. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
Egyptian paramedics load the corpses of Russian victims of a Russian passenger plane crash in the Sinai Peninsula, into a military plane at Kabret military air base by the Suez Canal on October 31, 2015. Egypt's government said 15 bodies have been recovered and transferred to a morgue so far from the site of the crash. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
SUEZ, EGYPT - OCTOBER 31: Egyptian officials receives the corpses of 34 passengers, found at crash site of Russian Airliner, at Kabret Military Base in Suez, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Mostafa El Shemy/Anadolu Agency/Getty Images)
Egyptian ambulances line up at Kabret military air base by the Suez Canal on October 31, 2015, after victims of a Russian airliner that crashed in the Sinai Peninsula were brought to the base before being transported to a morgue. Egypt's government said 15 bodies have been recovered and transferred to a morgue so far from the site of the crash. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
An Egyptian ambulance waits at Kabret military air base by the Suez Canal on October 31, 2015, after victims of a Russian airliner that crashed in the Sinai Peninsula were brought to the base before being transported to a morgue. Egypt's government said 15 bodies have been recovered and transferred to a morgue so far from the site of the crash. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
SUEZ, EGYPT - OCTOBER 31: Egyptian officials receives the corpses of 34 passengers, found at crash site of Russian Airliner, at Kabret Military Base in Suez, Egypt on October 31, 2015. A Russian Airbus-321 airliner with 224 people aboard crashed in Egypt's Sinai Peninsula on Saturday, according to the Egyptian Prime Minister's office. According to Egypts Civil Aviation Authority, the plane lost contact with air-traffic controllers shortly after taking off from the Egyptian Red Sea resort city of Sharm el-Sheikh en route to St Petersburg. (Photo by Alaa El Kassas/Anadolu Agency/Getty Images)
Egyptian ambulances carrying the corpses of Russian victims of a Russian passenger plane crash in the Sinai Peninsula, off load the bodies into a military aircraft at Kabret military air base by the Suez Canal on October 31, 2015. Egypt's government said 15 bodies have been recovered and transferred to a morgue so far from the site of the crash. AFP PHOTO / KHALED DESOUKI (Photo credit should read KHALED DESOUKI/AFP/Getty Images)
Egyptian police officers stand guard outside the Zeinhom Morgue in Cairo on October 31, 2015, as they wait for the victims of the Russian charter plane. A Russian plane carrying 224 people crashed in a mountainous part of Egypt's Sinai Peninsula, killing everyone on board, officials said. AFP PHOTO /MOHAMED EL-SHAHED (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images)
Egyptian police officers stand guard, next to graffiti condemning police brutality, outside the Zeinhom Morgue in Cairo on October 31, 2015, as they wait for the victims of the Russian charter plane. A Russian plane carrying 224 people crashed in a mountainous part of Egypt's Sinai Peninsula, killing everyone on board, officials said. AFP PHOTO /MOHAMED EL-SHAHED (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images)
Egyptian police officers stand guard outside the Zeinhom Morgue in Cairo on October 31, 2015, as they wait for the victims of the Russian charter plane. A Russian plane carrying 224 people crashed in a mountainous part of Egypt's Sinai Peninsula, killing everyone on board, officials said. AFP PHOTO /MOHAMED EL-SHAHED (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images)
Egyptian police officers stand guard outside the Zeinhom Morgue in Cairo on October 31, 2015, as they wait for the victims of the Russian charter plane. A Russian plane carrying 224 people crashed in a mountainous part of Egypt's Sinai Peninsula, killing everyone on board, officials said. AFP PHOTO /MOHAMED EL-SHAHED (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images)
Egyptian police officers stand guard outside the Zeinhom Morgue in Cairo on October 31, 2015, as they wait for the victims of the Russian charter plane. A Russian plane carrying 224 people crashed in a mountainous part of Egypt's Sinai Peninsula, killing everyone on board, officials said. AFP PHOTO /MOHAMED EL-SHAHED (Photo credit should read MOHAMED EL-SHAHED/AFP/Getty Images)
ALTERNATIVE CROP - In this photo taken on Tuesday, Oct. 20, 2015, The Russian airline Kogalymaviaâs Airbus A321 with a tail number of EI-ETJ on an airstrip of Moscowâs Domodedovo international airport, outside Moscow, Russia. Russia's civil air agency is expected to have a news conference shortly to talk about the Russian Metrojet passenger plane EI-ETJ, that Egyptian authorities say has crashed in Egypt's Sinai peninsula. (AP Photo/Tatiana Belyakova)
Map locates area in Egypt where a Russian airliner crashed Saturday; 3c x 4 inches; 146 mm x 101 mm;
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

Confirmation that militants brought down the airliner could have a devastating impact on Egypt's lucrative tourist industry, which has suffered from years of political turmoil and was hit last week when Russia, Turkey and several European countries suspended flights to Sharm al-Sheikh and other destinations.

It could also mark a new strategy by the hardline Islamic State group which holds large parts of Syria and Iraq.

Asked to explain the remaining 10 percent margin of doubt, the investigator declined to elaborate, but Muqaddam cited other possibilities on Saturday including a fuel explosion, metal fatigue in the plane or lithium batteries overheating.

He said debris was scattered over a 13-km (8-mile) area "which is consistent with an in-flight break-up".

Watch more coverage below:

Memorial Held for Russia Plane Dead

"GAME CHANGER"

"What happened in Sharm al-Sheikh last week, and to a lesser extent with the ... (Germanwings) aircraft, are game changers for our industry," Emirates Airlines President Tim Clark said, referring to the crash of a Germanwings airliner in the French Alps in March, believed crashed deliberately by its co-pilot.

"They have to be addressed at industry level because no doubt the countries -- U.S., Europe -- I would think will make some fairly stringent, draconian demands on the way aviation works with security," he said at the Dubai Airshow.

Clark said he had ordered a security review but was not suspending any flights as a result of the disaster. Emirates does not operate regular flights to Sharm al-Sheikh.

British Foreign Secretary Philip Hammond also said the incident could lead to changes in flight security.

"If this turns out to be a device planted by an ISIL operative or by somebody inspired by ISIL, then clearly we will have to look again at the level of security we expect to see in airports in areas where ISIL is active," Hammond told the BBC.

Islamic State, which wants to establish a caliphate in the Middle East, is also called ISIS or ISIL.

Islamic State militants fighting security forces in Egypt's Sinai Peninsula have said they brought down the aircraft as revenge for Russian air strikes against Islamist fighters in Syria. They said they would eventually tell the world how they carried out the attack.

If the group was responsible, it would have carried out one of the highest profile killings since al Qaeda flew passenger planes into New York's World Trade Center in September 2001.

Russia has returned 11,000 of its tourists from Egypt in the last 24 hours, RIA news agency said on Sunday, a fraction of the 80,000 Russians who were stranded by the Kremlin's decision on Friday to halt all flights to Egypt.

In St Petersburg, where the flight was headed on Oct. 31, the bell of St Isaac's Cathedral rang 224 times and a service was held in memory of the victims.

Russia has sent specialists to conduct a safety audit of Egypt's airports and to provide recommendations on additional measures, Arkady Dvorkovich, deputy prime minister, was quoted as saying by Russian agencies.

READ MORE: Voting smooth in Myanmar's first free election for 25 years

Dvorkovich, the head of a government group created on Friday to deal with suspended flights to Egypt, added a second group was going to Egypt on Sunday and a third would be sent later.

Britain, which has 3,000 nationals waiting to return home, has sent a team of 70 people, including 10 aviation specialists working at Sharm al-Sheikh airport to make sure security measures are being followed.

Eight flights were expected to take British tourists back home on Sunday.

(Additional reporting by Tim Hepher and Nadia Saleem in Dubai, Ahmed Aboulenein in Sharm al-Sheikh, William James in London, Denis Pinchuk in Moscow and Mikhail Antonov in St. Petersburg; Writing by Michael Georgy and Dominic Evans; Editing by Janet Lawrence)

More from AOL.com:
Apple defeats US class action lawsuit over bag searches
Two dozen missing in vast mudflow of Brazil mine disaster
Yemen fighting kills more than 50: residents, medical sources

Read Full Story

People are Reading