KABUL/WASHINGTON (REUTERS) - The Afghan Taleban's leadership council met to start considering succession after a US drone strike in Pakistan targeted its commander, two Taleban sources told Reuters, in the strongest sign yet the insurgency had accepted he was dead.
The strike targeting Mullah Akhtar Mansour on Saturday was perhaps the most high-profile US incursion into Pakistan since the 2011 raid to kill Al-Qaeda leader Osama bin Laden and sparked a protest by Islamabad that its sovereignty had been violated.
If confirmed, Mansour's death could trigger a succession battle within a Taleban insurgency that has proven extremely resilient despite a decade and a half of US military deployments to Afghanistan.
The Taleban have not yet officially confirmed that Mansour was killed and there were conflicting accounts on Sunday, with the Afghan government declaring him dead, while Washington stopped just short of doing so.
"At this point, we're not quite prepared to confirm that he was killed, though it appears likely," US Homeland Security Secretary Jeh Johnson told "Fox News Sunday."
The Taleban sources said that Sunday's (May 22) meeting of the Rahbari Shura, or leadership council, included discussion of possible successors, including guerrilla commander Sirajuddin Haqqani.
Haqqani, who has a US$5 million (S$6.9 million) US bounty on his head, would likely prove an even more implacable foe of Afghan government forces and their US allies.
He is widely seen by US and Afghan officials as the most dangerous warlord in the Taleban insurgency, responsible for the most bloody attacks, including one last month in Kabul in which 64 people were killed.
"Based purely on matters of hierarchy, (Haqqani) would be the favourite to succeed Mansour," said Dr Michael Kugelman, a senior associate at the Woodrow Wilson Institute think tank.
The Taleban were also considering Mullah Mohammad Yaqoob, the son of Taleban founder Mullah Mohammad Omar, a potential unifier because of his father's name. Former Guantanamo detainee Mullah Abdul Qayyum Zakir and Mullah Sherin were also cited, the sources said.
The Saturday drone strike, which US officials said was authorised by President Barack Obama, showed the United States was prepared to go after the Taleban leadership in Pakistan, which the government in Kabul has repeatedly accused of sheltering the insurgents.
Pakistan protested on Sunday, saying the US government did not inform Prime Minister Nawaz Sharif beforehand.
"This is a violation of Pakistan's sovereignty," Mr Sharif told reporters in London, saying it was still unclear who was killed.
A US official, speaking on condition of anonymity, acknowledged that Washington only notified Pakistan after the operation.
It was unclear how long Mansour might have been inside Pakistan before the US strike. Pakistan's Foreign Ministry disclosed that a passport found at the site, bearing a different name, carried a valid Iranian visa.
It added that the purported passport holder was believed to have returned to Pakistan from Iran on Saturday, the day of the drone strike targeting Mansour. Photos of the passport, bearing the name Wali Muhammad, seen by Reuters showed a passing resemblance to some of the old photos available of Mansour.
If it is confirmed that Mansour had travelled to Iran before his death, it would raise new questions about the Taleban's use of neighbouring territories, including Iran.
The drone strike underscored the belief among US commanders that the Taleban under Mansour's leadership had grown increasingly close to militant groups like Al-Qaeda, posing a direct threat to US security.
Mansour had failed to win over rival factions within the Taleban after formally assuming the helm last year after the Taleban admitted Mullah Omar had been dead for more than two years.
US Secretary of State John Kerry said the United States had conducted a precision air strike that targeted Mansour "in a remote area of the Afghanistan-Pakistan border".
Mansour posed a "continuing, imminent threat" to US personnel and Afghans, Mr Kerry told a news conference while on a visit to Myanmar. "If people want to stand in the way of peace and continue to threaten and kill and blow people up, we have no recourse but to respond and I think we responded appropriately," he said.
Efforts to broker talks between the Afghan government and the Taleban had already stalled after a suicide attack in Kabul last month that prompted President Ashraf Ghani to prioritize military operations over negotiations.
But Mr Ghani's office said on Sunday the removal of Mansour could open the door to talks and that Taleban members who wanted to end bloodshed should return from "alien soil" and join peace efforts.
US experts were less optimistic, cautioning against the idea that the shake-up would diminish the Taleban's broader sense of strength, particularly given the uneven performance of US-backed Afghan forces last year and a pullback by Western troops.
"The Taleban have made considerable progress in Helmand (province) and elsewhere, so it's hard to see much incentive for them to start compromising now," a US intelligence official said on condition of anonymity.
The new US commander in Afghanistan is reviewing strategy, including whether to request broader powers to target Taleban insurgents and whether to seek a halt in plans to reduce the number of US forces in Afghanistan.
One US government analyst said the Taleban were likely encouraged by the upcoming US presidential election.
"The Taleban, the Haqqanis, (Pakistani intelligence) and everyone else knows that ... the election this fall isn't going to bring in someone who wants to send more American troops to retake territory the Afghans are losing," the analyst said.