The Taliban have appointed a successor to Mullah Omar, who led the movement for some 20 years, the BBC has learned.
The death of Mullah Omar – reported by the Afghan government on Wednesday – was confirmed by the Taliban on Thursday, the BBC has been told.
His deputy, Mullah Akhtar Mansour, will replace him, sources close to the Taliban leadership said.
Correspondents say the move is likely to divide the militants, and that many senior figures opposed the appointment.
Pakistan says peace talks it was due to hold between the Afghan government and the Taliban on Friday have been postponed.
The Foreign Ministry said this was at the Taliban’s request due to uncertainty over Mullah Omar’s death.
The Taliban leader died two years ago in a Karachi hospital according to Afghanistan, but Pakistan has always denied that he was in the country.
A Taliban statement said Omar’s family had confirmed his death, but it did not say where or when it had happened. It said he had died of a “sickness”.
Analysis: Waheed Massoud, BBC Afghan editor, Kabul
The naming of Mullah Mansour as Taliban leader was far from unanimous and followed days of intense debate.
Sources close to the movement’s leading council, or shura, say many senior commanders and other Taliban heavyweights were dismayed by the decision.
They are thought to include the movement’s top military commander, Mullah Qaum Zakir, as well as Tayeb Agha, the head of the Taliban’s political office in Qatar, and Mullah Habibullah, a member of the Quetta shura. They would have preferred Mullah Omar’s son, Yaqoob, to succeed him, and accuse pro-Pakistani circles of imposing Mullah Mansour on the rebels.
A Taliban statement distancing the movement from more talks with the Afghan government reflects splits over how to proceed.
Mullah Mansour is pro-talks. He is to be given the title of Supreme Leader – not Leader of the Faithful, the title that Mullah Omar had.
The group appointed Siraj Haqqani, a key leader in another major Afghan military group, the Haqqani network, as Mansour’s deputy, sources said.
Mansour becomes only the second person to lead the Taliban after Mullah Omar, who founded the group during Afghanistan’s civil war in the early 1990s.
His alliance with al-Qaeda leader Osama Bin Laden prompted the US-led invasion of Afghanistan in 2001.
He had been in hiding ever since, and although was not thought to have significant day-to-day involvement in the group remained a key figurehead.
The failure to prove that Mullah Omar was alive was a major factor behind the defection of several senior Taliban commanders to the so-called Islamic State group, according to the BBC’s former Kabul correspondent, David Loyn.