British IS leader Jihadi John 'probably' killed in air strike

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Secretary Kerry: 'Still Assessing' Airstrike That Targeted 'Jihadi John'

The United States targeted British Islamic State leader "Jihadi John" in an air attack in northern Syria which Britain said would "strike at the heart of Islamic State" if the militant's death is confirmed.

British Prime Minister David Cameron said the death of Mohammed Emwazi, who was known as Jihadi John after appearing in videos showing the killings of U.S. and British hostages, could not yet be confirmed and the Pentagon said it was still assessing the effectiveness of the strike.

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But a U.S. official said Thursday's attack in the town of Raqqa, Islamic State's de facto capital, probably killed Emwazi and the Syrian Observatory for Human Rights, a monitoring group, quoted sources in Raqqa as saying he had been blown to pieces.

See photos of "Jihadi John" during last year's string of beheadings:

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Jihadi John (ISIS, ISIL, Islamic State)
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British IS leader Jihadi John 'probably' killed in air strike
This image made from militant video, which has been verified by SITE Intel Group and is consistent with other AP reporting, shows Mohammed Emwazi , known as "Jihadi John," holding a knife. A U.S. drone strike targeted a vehicle in Syria believed to be transporting the masked Islamic State militant known as "Jihadi John" on Thursday, Nov. 12, 2015 according to American officials. Whether the strike killed the British man who appears in several videos depicting the beheadings of Western hostages was not known, officials said. (SITE Intel Group via AP)
A screen grab from a video posted to YouTube by ISIS that claims to show journalist James Foley, who was abducted in 2012 while covering the Syria civil war, being beheaded. (Photo via YouTube)
BREAKING - Jihadi John revealed - the first picture of Mohammed Emwazi as an adult http://t.co/rxdU5ycD2D
This image made from militant video, which has been verified by SITE Intel Group and is consistent with other AP reporting, shows Mohammed Emwazi , known as "Jihadi John," holding a knife. A U.S. drone strike targeted a vehicle in Syria believed to be transporting the masked Islamic State militant known as "Jihadi John" on Thursday, Nov. 12, 2015 according to American officials. Whether the strike killed the British man who appears in several videos depicting the beheadings of Western hostages was not known, officials said. (SITE Intel Group via AP)
British Aid Worker David Haines (Photo via YouTube)
In this file still image from an undated video released by Islamic State militants on Tuesday, Aug. 19, 2014, purports to show journalist Steven Sotloff being held by the militant group. Islamic State militants called American journalist James Foley's gruesome videotaped beheading revenge for U.S. airstrikes against the group, and they still hold at least three other Americans hostage, including Sotloff. (AP Photo, File)
Screen shot from an Internet video released Friday that purports to show an ISIS militant beheading British aid worker Alan Henning, who had been taken hostage by the extremist group.
FILE - This still image from undated video released by Islamic State militants on Oct. 3, 2014, purports to show the militant known as Jihadi John. A U.S. drone strike targeted a vehicle in Syria believed to be transporting the masked Islamic State militant known as "Jihadi John" on Thursday, Nov. 12, 2015, according to American officials. Whether the strike killed the British man who appears in several videos depicting the beheadings of Western hostages was not known, officials said. (AP Photo/File)
ED NOTE: GRAPHIC CONTENT - This image made from a video released by Islamic State militants on Saturday, Jan. 31, 2015, purports to show a militant standing next to Japanese journalist Kenji Goto before his beheading by the militant group. Goto was captured in October 2014, after he traveled to Syria to try to win the release of Haruna Yukawa. (AP Photo)

Islamic State of Iraq and the Levant fighter threatens to behead Japanese hostages Journalist Kenji Goto Jogo, left, and military contractor Haruna Yukawa in a propaganda video released by the organization January 20, 2015.

(Photo: Alamy)

Kuwaiti lawyer Salem al-Hashash talks to reporters in his office in Kuwait City on Sunday, March 8, 2015. The former lawyer for the father of Mohammed Emwazi, unmasked as "Jihadi John" last month, said there is no evidence proving the masked Islamic State militant is his client's son. (AP Photo/Hussain al-Qatari)
LONDON, ENGLAND - FEBRUARY 26: The home where the British Daesh (Islamic State of Iraq and the Levant) militant known as 'Jihadi John' is claimed to have once lived, is pictured on February 26, 2015 in London, England. Mohammed Emwazi has been pictured in videos showing the beheading of Western hostages. (Photo by Tolga Akmen/Anadolu Agency/Getty Images)
An arrangment of British daily newspapers photographed in London on February 27, 2015 shows the front-page headlines and stories regarding the identification of the masked Islamic State group militant dubbed 'Jihadi John'. The British headlines were dominated on Febryary 27 by the story of the identification of the Islamic State executioner. 'Jihadi John', the masked Islamic State group militant believed responsible for beheading of at least five Western hostages, has been named as Kuwaiti-born computing graduate Mohammed Emwazi from London. AFP PHOTO / DANIEL SORABJI (Photo credit should read DANIEL SORABJI/AFP/Getty Images)
EXCLUSIVE PICS: The Man Utd & S Club 7 fan who became I.S. executioner 'Jihadi John' unmasked http://t.co/BBES6nVowK http://t.co/5v9pjNHcqU
James Foley's mother says she 'forgives' Mohammed Emwazi http://t.co/dPHi1gvRK1 http://t.co/b1xtfU456u
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"A car carrying four foreign Islamic State leaders, including one British Jihadi was hit by U.S. air strikes right after the governorate building in Raqqa city," Rami Abdulrahman, Director of the UK-based Observatory told Reuters.

He initially quoted sources in Raqqi as saying the body of "an important British Jihadi" was in the town's hospital but later quoted them as saying Emwazi's body, and those of his three militant comrades, had been left in charred pieces.

Emwazi took part in videos showing the murders of U.S. journalists Steven Sotloff and James Foley, U.S. aid worker Abdul-Rahman Kassig, British aid workers David Haines and Alan Henning, Japanese journalist Kenji Goto, and other hostages.

RELATED: See photos of U.S.-led airstrikes in Syria

20 PHOTOS
U.S.-led airstrikes in Syria
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British IS leader Jihadi John 'probably' killed in air strike
FILE - In this Monday, Oct. 20, 2014 file photo, thick smoke and flames from an airstrike by the U.S.-led coalition rise in Kobani, Syria, as seen from a hilltop on the outskirts of Suruc, at the Turkey-Syria border. For a force that has built its reputation on projecting an aura of momentum and invincibility, the prolonged stalemate in Kobani is a setback for Islamic State militants with potential implications in terms of recruitment and support. Nearly two months after it launched its lightning assault on the small Kurdish town, the group is bogged down with an increasingly entrenched and costly battle in which hundreds of its fighters have been killed and a good deal of its military apparatus destroyed. (AP Photo, Lefteris Pitarakis, File)
Smoke rises from the Syrian city of Kobani, following an airstrike by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Monday, Nov. 17, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
Smoke rises from the Syrian city of Kobani, following airstrikes by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Monday, Nov. 17, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
Armed people, believed to be Kurdish fighters, stand behind a wall, bottom center-left, as smoke rises from the Syrian city of Kobani, following airstrikes by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Monday, Nov. 17, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
Smoke rises from the Syrian city of Kobani, following airstrikes by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Monday, Nov. 17, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
FILE - In this Nov. 17, 2014 file photo, smoke rises from the Syrian city of Kobani, following an airstrike by the U.S.-led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border. The mass beheadings of Egyptian Christians by militants in Libya linked to the Islamic State group have thrown a spotlight on the threat the extremists pose beyond their heartland in Syria and Iraq, where they have established a self-declared proto-state. Militants in several countries - including Libya, Egypt, Algeria, Yemen and Saudi Arabia - have pledged allegiance to IS leader Abu Bakr al-Baghdadi. (AP Photo/Vadim Ghirda, File)
A tractor drives on agricultural fields as smoke rises from an Islamic State group position in eastern Kobani, after an airstrike by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Saturday, Nov. 8, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
Two bombs, seen on top right, fall on an Islamic State fighters' position in the town of Kobani during airstrikes by the US led coalition, seen from the outskirts of Suruc, near the Turkey-Syria border, Wednesday, Oct. 29, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
This image made from gun-camera video taken on July 4, 2015 and released by United States Central Command shows an airstrike on a bridge near Islamic State group-held Raqqa, Syria, that was a key transit route for the militants. After billions of dollars spent and more than 10,000 extremist fighters killed, the Islamic State group is fundamentally no weaker than it was when the U.S.-led bombing campaign began a year ago, American intelligence agencies have concluded. (U.S. Central Command via AP)
This image made from gun-camera video taken on July 4, 2015 and released by United States Central Command shows an airstrike on a main road and transit route near the Islamic State group-held Raqqa, Syria. After billions of dollars spent and more than 10,000 extremist fighters killed, the Islamic State group is fundamentally no weaker than it was when the U.S.-led bombing campaign began a year ago, American intelligence agencies have concluded. (U.S. Central Command via AP)
In this photo taken from the Turkish side of the border between Turkey and Syria, in Akcakale, southeastern Turkey, people watch as smoke from a US-led airstrike rises over the outskirts of Tal Abyad, Syria, Monday, June 15, 2015. Thousands of Syrians cut through the border fence and crossed over into Turkey Sunday, fleeing intense fighting in northern Syria between Kurdish fighters and jihadis. (AP Photo/Lefteris Pitarakis)
In this photo taken from the Turkish side of the border between Turkey and Syria, in Akcakale, Sanliurfa province, southeastern Turkey, smoke from a US-led airstrike rises over the outskirts of Tal Abyad, Syria, Sunday, June 14, 2015. Syrian Kurdish fighters closed in on the outskirts of a strategic Islamic State-held town on the Turkish border Sunday, Kurdish officials and an activist group said, potentially cutting off a key supply line for the extremists' nearby de facto capital. Taking Tal Abyad, some 80 kilometers (50 miles) from the Islamic State stronghold of Raqqa, would mean the group wouldn't have a direct route to bring in new foreign militants or supplies.(AP Photo/Lefteris Pitarakis)
Turkish soldiers guard the border area with Syria in Akcakale, southeastern Turkey, as smoke from a fire caused by a US-led airstrike rises over the outskirts of Tal Abyad, Syria, Monday, June 15, 2015. A day after thousands of Syrians cut through the border fence and crossed over into Turkey, fleeing intense fighting in northern Syria between Kurdish fighters and Islamic State group, Turkish army retook control. (AP Photo/Lefteris Pitarakis)
FILE - In this Oct. 22, 2014, file photo, thick smoke from an airstrike by the US-led coalition rises in Kobani, Syria, as seen from a hilltop on the outskirts of Suruc, at the Turkey-Syria border. For four months, Syrian Kurdish fighters battled Islamic State militants in the rubble-strewn streets and crumpled buildings in the town of Kobani as U.S. aircraft pounded the extremists from the skies above. (AP Photo/Lefteris Pitarakis, File)
A bombs, seen top left, falls on an Islamic State position in eastern Kobani, during an airstrike by the US led coalition, seen from a hilltop outside Suruc, on the Turkey-Syria border Saturday, Nov. 8, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
Children run on a hillside as smoke rises from an Islamic State fighters position in the town of Kobani during airstrikes by the US led coalition, seen from the outskirts of Suruc, near the Turkey-Syria border, Wednesday, Oct. 29, 2014. Kobani, also known as Ayn Arab, and its surrounding areas, has been under assault by extremists of the Islamic State group since mid-September and is being defended by Kurdish fighters. (AP Photo/Vadim Ghirda)
In this photo taken Tuesday, March 10, 2015, members of a U.S. Air Force munitions team assemble guided bombs to support the 379th Air Expeditionary Wing at the al-Udeid Air Base in Qatar. The base is the regional nerve center for the air war against the militants who have taken over nearly a third of Iraq and Syria. That makes it the main hub for coordinating warplanes from the U.S. and 11 other nations in the coalition carrying out bombing raids. (AP Photo/Adam Schreck)
In this photo taken Monday, March 9, 2015, a B-1 bomber prepares to land after finishing a mission at the al-Udeid Air Base in Doha, Qatar. The base is the regional nerve center for the air war against the militants who have taken over nearly a third of Iraq and Syria. That makes it the main hub for coordinating warplanes from the U.S. and 11 other nations in the coalition carrying out bombing raids. (AP Photo/Osama Faisal)
A U.S. military officer looks out at the flight deck of the French navy aircraft carrier Charles de Gaulle in the Persian Gulf as the U.S. helicopter prepares for takeoff Thursday, March 19, 2015. The Charles de Gaulle, France's only aircraft carrier and the flagship of the French navy, arrived in the Persian Gulf last month to help provide additional air power to the U.S.-led coalition conducting airstrikes against the Islamic State militants who have seized a third of Iraq and Syria. (AP Photo/Hasan Jamali)
FILE - In this Aug. 10, 2014 file photo, an aircraft lands after missions targeting the Islamic State group in Iraq from the deck of the U.S. Navy aircraft carrier USS George H.W. Bush in the Persian Gulf. Combined U.S.-Arab airstrikes at the heart of the Islamic State group's military strongholds in Syria achieved their strategic aim of showing the extremists that their savage attacks will not go unanswered, the top American military officer said Tuesday, Sept. 23, 2014. (AP Photo/Hasan Jamali, File)
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Shown in the videos dressed entirely in black, a balaclava covering all but his eyes and the bridge of his nose, Jihadi John became a menacing symbol of Islamic State brutality and one of the world's most wanted men. He was born in Kuwait but brought up in Britain.

The British government said it had "been working hand in glove with the Americans" to defeat Islamic State "and to hunt down those murdering Western hostages."

"BARBARIC MURDERER"

Speaking outside his Downing Street residence, Cameron described Emwazi as "a barbaric murderer" who "posed an ongoing and serious threat to innocent civilians, not only in Syria but around the world and in the United Kingdom too".

"If this strike was successful -- and we still await confirmation of that -- it will be a strike at the heart of ISIL (Islamic State)," he said in comments shown live on television.

"It will demonstrate to those who would do Britain, our people and our allies harm, we have a long reach, we have unwavering determination and we never forget about our citizens."

He said the U.S. air strike resulted from a combined effort between Britain and the United States and was an act of self-defense: "It was the right thing to do".

U.S. President Barack Obama has promised justice after the deaths of American hostages and the United States is seeking to increase pressure on Islamic State fighters, who have seized parts of Syria and Iraq, and who Obama has vowed to defeat.

The pressure includes U.S. plans to deploy dozens of special operations forces to Syria, deliver more weaponry to U.S.-backed Syrian fighters and to thicken U.S. air strikes against the militant group.

(Reporting by John Davison and Mariam Karouny, editing by Samia Nakhoul and Timothy Heritage)

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