At the Taliban meeting this week where Mullah Akhtar Mohammad Mansour was named as the Islamist militant group's new head, several senior figures in the movement, including the son and brother of late leader Mullah Omar, walked out in protest.
The display of dissent within the group's secretive core is the clearest sign yet of the challenge Mansour faces in uniting a group already split over whether to pursue peace talks with the Afghan government and facing a new, external threat - Islamic State.
Rifts in the Taliban leadership are likely to widen after confirmation this week of the death of elusive founder Omar.
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Exclusive: Walkout at Taliban leadership meeting raises specter of split
An Afghan newspaper headlines pictures of the new leader of the Afghan Taliban, Mullah Akhtar Mohammad Mansoor, left, and Mullah Mohammad Omar, in Kabul, Afghanistan, Saturday, Aug. 1, 2015. The new leader of the Afghan Taliban vowed to continue his group's bloody, nearly 14-year insurgency in an audio message released Saturday, urging his fighters to remain unified after the death of their longtime leader. (AP Photo/Rahmat Gul)
Graphic shows gives some information on the top leaders in the Taliban; 2c x 4 1/2 inches; 96.3 mm x 114 mm;
An Afghan man holds a calendar bearing the images of Afghan leaders including the Taliban's late chief Mullah Omar (bottom 2nd L) in Kandahar on July 31, 2015. The Taliban named Mullah Akhtar Mansour as their new leader July 31, a historic power transition that raises hopes the relative moderate's leadership will pave the way for an end to Afghanistan's bloody war. AFP PHOTO / Javed Tanveer (Photo credit should read JAVED TANVEER/AFP/Getty Images)
An Afghan shop clerk shows a calendar with pictures of Afghan leaders including Mullah Mohammad Omar, center, in Kandahar, south of Kabul, Afghanistan, Thursday, July 30, 2015. The Taliban confirmed the death of longtime leader Mullah Omar and appointed his successor Thursday, as a new round of peace talks was indefinitely postponed amid concerns over how committed the new leadership is to ending the militant group's 14-year insurgency. (AP Photo/Barialai Khoshhal)
Hafiz Saeed, leader of Pakistan's religious group Jamaatud Dawa, front, leads a funeral prayers for Taliban leader Mullah Mohammad Omar at a mosque in Lahore, Pakistan, Thursday, July 30, 2015. Afghanistan's Taliban on Thursday confirmed the death of Mullah Omar, who led the group's self-styled Islamic emirate in the 1990s, sheltered al-Qaida through the 9/11 attacks and led a 14-year insurgency against U.S. and NATO troops. (AP Photo/Ahmed Ali)
An Afghan store clerk shows a calendar with pictures of Afghan leaders including Mullah Mohammad Omar, bottom row, second left, in Kandahar, south of Kabul, Afghanistan, Thursday, July 30, 2015. The Taliban confirmed the death of longtime leader Mullah Omar and appointed his successor Thursday, as a new round of peace talks was indefinitely postponed amid concerns over how committed the new leadership is to ending the militant group's 14-year insurgency. (AP Photo/Barialai Khoshhal)
A man reads a newspaper at a news stand where local newspapers are displayed carrying headlines about the death of Taliban leader Mullah Mohammad Omar, in Peshawar, Pakistan, Thursday, July 30, 2015. Afghanistan's Taliban on Thursday confirmed the death of Mullah Omar, who led the group's self-styled Islamic emirate in the 1990s, sheltered al-Qaida through the 9/11 attacks and led a 14-year insurgency against U.S. and NATO troops. (AP Photo/Mohammad Sajjad)
Deputy press secretary Eric Schultz speaks to the media during the daily briefing in the Brady Press Briefing Room of the White House in Washington, Wednesday, July 29, 2015. White House says reports of Taliban leader Mullah Mohammad Omar's death are credible.(AP Photo/Pablo Martinez Monsivais)
Afghan security forces inspect the site of a suicide attack after clashes with Taliban fighters in front of the Parliament, in Kabul, Afghanistan, Monday, June 22, 2015. The Taliban launched a complex attack on the Afghan parliament Monday, with a suicide car bomber striking at the entrance and gunmen battling police as lawmakers were meeting inside to confirm the appointment of a defense minister, police and witnesses said. (AP Photo/Rahmat Gul)
Deputy presidential spokesman Zafar Hashimi speaks during a press conference in Kabul on July 29, 2015. The Afghan government is investigating reports of the death of Taliban supremo Mullah Omar, a presidential spokesman said on July 29, amid frenzied speculation about the rumoured demise of the reclusive warrior-cleric.The Taliban have not officially confirmed the death of Mullah Omar, who has not been seen publicly since the 2001 US-led invasion of Afghanistan toppled the Taliban government in Kabul. (Photo credit: SHAH MARAI/AFP/Getty Images)
Pakistan members of Jamiat Nazriati party march in a rally to pay tribute to Afghanistan's deceased Taliban chief Mullah Omar, in Quetta on August 2, 2015. New Taliban leader Mullah Akhtar Mansour called for unity in the movement August 1, in his first audio message since becoming head of the group that faces deepening splits following the death of longtime chief Mullah Omar. AFP PHOTO / Banaras KHAN (Photo credit should read BANARAS KHAN/AFP/Getty Images)
An Afghan man reads a local newspaper at a news stand carrying a headline about the new leader of the Afghan Taliban, Mullah Akhtar Mohammad Mansoor, in Kabul, Afghanistan, Saturday, Aug. 1, 2015. The new leader of the Afghan Taliban vowed to continue his group's bloody, nearly 14-year insurgency in an audio message released Saturday, urging his fighters to remain unified after the death of their longtime leader. (AP Photo/Rahmat Gul)
Supporters of a Pakistani religious group 'Jamaat-ud-Dawa' attend funeral prayers for Taliban leader Mullah Mohammad Omar at a mosque in Islamabad, Pakistan, Saturday, Aug. 1, 2015. Afghanistan's Taliban on Thursday confirmed the death of Mullah Omar, who led the group's self-styled Islamic emirate in the 1990s, sheltered al-Qaida through the 9/11 attacks and led a 14-year insurgency against U.S. and NATO troops. (AP Photo/Anjum Naveed)
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Mansour, Omar's longtime deputy who has been effectively in charge for years, favors talks to bring an end to more than 13 years of war. He recently sent a delegation to inaugural meetings with Afghan officials hosted by Pakistan, hailed as a breakthrough.
But Mansour, 50, has powerful rivals within the Taliban who oppose negotiations, notably battlefield commander Abdul Qayum Zakir, a former inmate of the U.S. prison in Cuba's Guantanamo Bay.
Zakir is pushing for Mullah Omar's son Yaqoob to take over the movement, and a sizeable faction also supports Yaqoob.
Yaqoob and his uncle Abdul Manan, Omar's younger brother, were among several Taliban figures who walked out of Wednesday's leadership meeting held in the western Pakistani city of Quetta, according to three people who were at the shura, or gathering.
"Actually, it wasn't a Taliban Leadership Council meeting. Mansoor had invited only members of his group to pave the way for his election," said one of the sources, a senior member of Taliban in Quetta.
"And when Yaqoob and Manan noticed this, they left the meeting."
PEACE TALKS IN JEOPARDY
The leadership shura, or gathering, was held outside Quetta, where many Taliban leaders have been based since their hardline regime in Afghanistan was toppled in a 2001 U.S.-led military intervention.
Afghan Taliban leaders have long had sanctuaries in Pakistan, even as Pakistani government officials have denied offering support in recent years.
Mansour leads the Taliban's strongest faction and appears to control most of its spokesmen, websites and statements, said Graeme Smith, senior Afghanistan analyst for the think-tank International Crisis Group.
But some intelligence officials estimate Mansour only directly controls about 40 percent of fighters in the field, he said.
That could make it difficult for him to deliver on any ceasefire that could emerge from future negotiations.
And Taliban insiders say that by sending a three-member delegation to meet Afghan officials in the Pakistani resort of Murree earlier in July, Mansour sparked new criticism.
Especially riled were members of the Taliban's political office in Qatar, who insisted only they were empowered to negotiate.
"People ... were not happy with Mullah Mansour when he agreed with Pakistan ... to hold a meeting with Kabul," said a Taliban commander based in Quetta.
"The Qatar office wasn't taken into confidence before taking such an important decision."
The Quetta shura has sent a six-member team to Qatari capital Doha to meet with one of its leaders, Tayyab Agha, seeking his support for Mansour, according to another Taliban source close to the leadership.
RELATIONS WITH PAKISTAN
The divisions threaten a formal split in the Taliban. They also provide an opening to rival Islamic State (IS), the Middle East-based extremist movement that has attracted renegade Taliban commanders in both Afghanistan and Pakistan.
This month, two Afghan militant groups swore allegiance to Islamic State, and more could follow suit.
Despite threats both internal and external, Taliban fighters have been gaining territory inAfghanistan, where they are trying to topple the Western-backed government.
This week another district, this time in the south, fell to insurgents, who have exploited the absence of most NATO troops after they withdrew at the end of last year.
Opponents of Mansour criticize him for being too close to Pakistan's military, which has long been accused of supporting the Afghan insurgency to maintain regional influence.
Pakistan has pushed Taliban leaders based in its territory hard to come to the negotiating table at the request of ally China and Afghan President Ashraf Ghani.
But many Taliban, and some Afghan officials, fear the recent talks are a ploy by Pakistanto retain control. The Pakistanis deny that.
Still, Mansour cannot afford to alienate Pakistan, said Saifullah Mahsud of the Islamabad-based FATA Research Centre.
"No matter who is in charge of the Taliban in Afghanistan, they will have no choice but to have a good relationship with the Pakistani state. It's a matter of survival," Mahsud said.
"I don't think this agreement to go to the negotiating table is determined by personality; it's more about the circumstances."
Despite the opposition, Mansour retains a personal power base within the Taliban, and if he can keep the movement together it could lead to a new era for the insurgents.
Bette Dam, author of an upcoming biography of Mullah Omar, said the supreme leader's absence paralyzed many Taliban officials.
Mansour could provide a more active focus for both the movement's rank-and-file and those seeking to engage the Taliban.
"If he gets the credibility, it might not be such bad news to have Mansour replace the invisible Mullah Omar," she said.