Senior sources within the Taliban on Sunday cast doubt on the authenticity of an audio message purporting to prove Mullah Akhtar Mansour was alive as Afghan officials said they were working to verify the clip.
The insurgent group released the 16-minute file on late Saturday following reports citing multiple intelligence and militant sources claiming the Taliban chief was killed in a firefight on Tuesday inside Pakistan.
But doubts continued to linger among the group's senior ranks, who are distrustful of their leadership following a two-year cover-up, from 2013-2015, of the death of the Taliban's founder and first leader Mullah Omar.
"I think it's a faked audio. I believe he's dead," a senior Taliban source told AFP on Sunday, adding that the group is buying time to select a new leader and bring their organisation out of "this sudden shock".
"We need more proof," he concluded.
A second senior source added: "I am not satisfied after hearing the clip that it belongs to Mansour," while a third said Mansour succumbed to his injuries on Thursday.
In the message, a man purporting to be Mansour said: "I have recorded this message to let everyone know that I am alive."
"I didn't have a fight with anyone, no meeting was held and I have not been to Kuchlak (near Quetta in Pakistan) in years. This is all enemy propaganda," the message added.
The man also offered his condolences to the relatives of civilians killed in the central Wardak province in a firefight between government forces and the Taliban on Friday -- three days after Mansour was allegedly shot.
Rahimullah Yousufzai, a Pakistani analyst and long-time observer of the Taliban, said the voice sounded like Mansour's. "I believe it is him," he said, but added questions would be asked over the delay in releasing the clip.
"Why did they wait almost five days to do that? If they'd done it earlier it might have been more effective," he said.
He added that uncertainty within the ranks had been compounded by the mystery surrounding the death of Mullah Omar.
Afghan intelligence officials announced his death in July, with the Taliban later confirming their founder had died in 2013, apparently due to illness.
Mansour was declared Taliban leader on July 31, but splits immediately emerged in the group, with some top leaders refusing to pledge their allegiance to the new leader saying the process to select him was rushed and biased.