KABUL: The Taliban on Monday admitted covering up longtime leader Mullah Omar's death for more than two years, saying he died in 2013 as was first claimed by the Afghan intelligence.

The group had continued as recently as July to release official statements in the name of Omar, who had not been seen in public since the Taliban were toppled from power in Kabul in 2001.

They confirmed on July 30 that he had died but did not say when, deepening internal divisions as many insurgents accused the leadership of covering up his death for two years.

Know more: Afghan govt confirms Omar’s death

A Taliban statement Monday admitted for the first time that he died on April 23, 2013. The detail was buried in a biography of new leader Mullah Akhtar Mansour, Omar's longtime deputy.

"Several key members of the supreme leading council of the Islamic Emirate (Taliban) and authentic religious scholars together decided on concealing the tragic news of passing away of (Omar)... and keep this secret limited to the very few colleagues who were already informed of this incorrigible loss," the biography said.

"One of the main reasons behind this decision was... that 2013 was considered the final year of power testing between the mujahidin and foreign invaders who... had announced that at the end of 2014, all military operations by foreign troops would be concluded."

Take a look: Mullah Omar did not die in Pakistan, say Afghan Taliban

North Atlantic Treaty Organisation (Nato) ended its combat mission in Afghanistan last December and pulled out the bulk of its troops although a 13,000-strong residual force remains for training and counter-terrorism operations.

Confirmation of Omar's death and Mansour's contentious ascension triggered a power struggle within the Taliban at a time when the rival Daesh or self-styled Islamic State group is making gradual inroads into Afghanistan.

Afghan Taliban offer leader's biography amid power struggle

The Afghan Taliban published a biography of their new leader Monday as hundreds of insurgents met to resolve a dispute over his appointment following the death of figurehead Mullah Mohammad Omar.

The detailed biography, emailed to journalists in five languages, offers the story of Mullah Akhtar Mansour, who now leads the Taliban in its fight against the Afghan government.

Mansour was named as the Taliban's leader last month after the Afghan government revealed that Mullah Omar died in 2013. But family of Mullah Omar objected, saying the vote to elect Mansour was not representative of the group, sparking an internal power struggle.

Know more: Taliban leaders swear allegiance to Mullah Mansour

Hundreds of Taliban fighters, including battlefield commanders, are meeting in the Pakistani city of Quetta in an effort to resolve the leadership dispute.

The release of the biography appears to be an attempt by Mansour's supporters to shore up his position and consolidate his power ahead of the meeting's delegates making a final decision about who leads them.

That decision could be made within days.

Habibullah Fouzi, a diplomat under the Taliban and now a member of the Afghan government's High Peace Council charged with ending the war, said there could be more dissension coming in the Taliban.

He said many rank-and-file members supported Mullah Omar's brother, Manan, and son, Yaqub, who have challenged Mansour's appointment.

"It is clear that Mullah Mansour has been imposed into this position by others," Fouzi said.

The biography released by the Talban's media office described Mansour being appointed "in full compliance with Islamic Shariah law," making him "totally legitimate."

Some top leaders including Omar's son and brother have refused to pledge allegiance to new leader Mansour, saying the process to select him was rushed and biased.

Know more: Mullah Mansour welcomes Zawahiri's pledge of loyalty

The Taliban have suffered a string of defections to IS.

The power struggle, observers say, could be a very effective recruitment tool for IS, potentially helping it attract more Taliban turncoats.