Afghan security forces patrol in Kunduz, the site of continued conflict with the Taliban, on April 30, 2015
The Taliban on Thursday distanced itself from peace talks that had been expected this week with the Afghan government, while making no comment on Kabul's reported death of their leader Mullah Omar.
Afghanistan on Wednesday said Omar died two years ago in Pakistan, in the first such official confirmation from Kabul after unnamed government and militant sources reported the demise of the reclusive warrior-cleric.
The insurgents have not officially confirmed his death, and the claim -- just two days before a fresh round of talks were expected -- cast doubt over the tenuous peace process.
"Media outlets are circulating reports that peace talks will take place very soon... either in the country of China or Pakistan," the Taliban said in an English-language statement posted on their website on Thursday.
"(Our) political office... are not aware of any such process."
Hours later the Pakistani foreign ministry said the second round of talks, which had been due to take place on Friday, had been postponed.
The ministry said the Taliban leadership had asked for the postponement "in view of the reports regarding the death of Mullah Omar and the resulting uncertainty".
The Taliban's earlier statement was the first comment from the group, which has waged an almost 14-year insurgency against Afghan and foreign forces, since Kabul's dramatic announcement, of Omar's death, citing "credible information".
Omar has not been seen publicly since the 2001 US-led invasion of Afghanistan that toppled the Taliban government in Kabul.
Haseeb Sediqi, the spokesman for Afghanistan's National Directorate of Security, told AFP that Omar died in hospital in the Pakistani city of Karachi "under mysterious circumstances".
Rumours of Omar's ill-health and even death have regularly surfaced in the past, but the White House added weight to Kabul's latest assertion, calling reports of his demise "credible".
- 'Existential crisis' -
Omar's death would mark a significant blow to the Taliban, which is riven by internal divisions and threatened by the rise of the Islamic State group, the Middle East jihadist outfit that is making steady inroads in Afghanistan.
Afghan officials sat down with Taliban cadres earlier this month in Murree, a holiday town in the hills north of the Pakistani capital Islamabad, for their first face-to-face talks aimed at ending the bloody insurgency.
They had agreed to meet again in the coming weeks, drawing international praise, and Afghan officials pledged to press for a ceasefire in the second round.
Michael Kugelman, Afghanistan expert at the Washington-based Woodrow Wilson International Center for Scholars, said the "talks have... certainly lost their momentum".
"Announcement of Omar's death will spark an existential crisis for the Taliban, and the last thing that will be on its mind are peace talks. It will need to focus on its survival, not talks," Kugelman told AFP.
A statement from the Afghan presidential palace on Wednesday, however, said grounds for the discussions are more solid now than before, and implored all insurgents to join the peace process.
But many of the insurgents' ground commanders have openly questioned the legitimacy of the Taliban negotiators, exposing dangerous faultlines within the movement.
The split within the Taliban over the peace process has been worsened by the emergence of a local branch of the Islamic State group, which last year declared a "caliphate" across large areas of Iraq and Syria under its control.
The Taliban warned IS recently against expanding in the region, but this has not stopped some fighters, inspired by the group's success, defecting to swear allegiance to IS chief Abu Bakr al-Baghdadi instead of the invisible Mullah Omar.