It remains unclear whether Mansour survived the gunfight, which threatens to derail a renewed regional push to jump-start peace talks with the Taliban.
The clash broke out just four months after Mansour was appointed Taliban leader in an acrimonious leadership succession soon after the group belatedly confirmed longtime chief Mullah Omar’s death.
The Taliban officially rejected as “absolutely baseless” the reports of the firefight, which officials and militant sources said was triggered by an altercation at an insurgent gathering that cascaded out of control.
“We are trying to establish whether Mansour is dead or alive,” said Sultan Faizi, the spokesman for the Afghan first vice president.
“His situation is critical,” Faizi said, citing credible information.
A senior Pakistani intelligence official told AFP that Mansour had been “very seriously injured” in what he described as a “heavy exchange of fire” at a gathering of militant commanders near the Pakistani city of Quetta.
An Afghan intelligence official and multiple insurgent sources close to Mansour’s group confirmed the account to AFP, adding that the gunfight left at least four Taliban members dead and several others wounded.
The firefight exposes deepening divisions within the fractious militant movement, which saw its first formal split last month after a breakaway faction surfaced.
The rifts increase the risk of internecine clashes within the Taliban, which has lately seen a new resurgence under Mansour even as it confronts the rise of the rival Islamic State group in Afghanistan.
There was conflicting information on the location of the confrontation, with some sources claiming that it took place near the southern Afghan city of Kandahar, the spiritual birthplace of the Taliban.
But they all agreed the meeting was at the home of Abdullah Sarhadi, a commander in Mansour’s group and a former Guantanamo Bay detainee.
“There were differences on some points which later turned into harsh words, then Sarhadi opened fire and the others returned fire,” a Taliban source said.
It was unclear what the argument was about.
Mansour is reported to be under growing pressure from Pakistani intelligence to restart peace talks with Afghan authorities, a contentious issue that has prompted much rancour within hardline insurgent ranks.
– Growing rifts –
“The reports are still sketchy, but the sheer volume of rumours suggesting that something has happened to Mansour will pressure the Taliban to offer proof that he’s alive,” a Western official in Kabul told AFP.
“Simply posting denials on their website won’t be considered credible enough, especially after Mullah Omar’s death was concealed for years.”
A Taliban commander in the southern province of Helmand told AFP that the group will soon release an audio and video message from Mansour.
Mansour was declared Taliban leader on July 31 after the insurgents confirmed the death of Omar, who led the Islamist movement for some two decades.
But splits immediately emerged in the group, with some top leaders refusing to pledge allegiance to him, saying the process to select him was rushed and even biased.
Many were also unhappy that Omar’s death had been kept secret for two years — during which time annual Eid statements were issued in his name.
A breakaway faction of the Taliban led by Mullah Mohamed Rasool was formed last month, in the first formal split in the once-unified group.
But the insurgency has shown no signs of weakening despite the divisions.
They briefly captured the strategic northern city of Kunduz in September in their most spectacular victory in 14 years and opened new battlefronts across the country.
Pakistan, which wields considerable influence over the militants, hosted a historic first round of peace negotiations in July.
But the dialogue process stalled soon after Omar’s death was announced.
The United States and China have been pushing for the process to restart, but frosty ties between Islamabad and Kabul have been hampering those efforts.
Afghan President Ashraf Ghani this week voiced a willingness to revive the negotiations following a meeting with Pakistan’s Prime Minister Nawaz Sharif in Paris.
Rasool’s hardline faction, reported to be aligned to the Islamic State group, also poses a major challenge to talks.
Afghan officials on Wednesday confirmed reports of the death of his deputy, Mullah Dadullah, a prominent commander and a major rival to Mansour.
The splinter group denies Dadullah’s death but officials insist he was killed last month in a clash with Mansour loyalists.
The faction has so far not commented on whether it had a role in Mansour’s injury.