Afghan Taliban have named a deputy to former leader Mullah Akhtar Mansour as their new leader, a spokesman says in a statement, the group's first official confirmation that Mansour was killed in a US drone strike.

President Barack Obama confirms Taliban chief Mullah Akhtar Mansour is killed in a US air strike, hailing his death as an "important milestone" in efforts to bring peace to Afghanistan.

A breakaway Afghan Taliban faction has appointed its own leader, underlining deep divisions in the group following the death of founder Mullah Omar.

The Afghan Taliban have confirmed covering up their former leader Mullah Omar's death for more than two years.