The US military has conducted an air strike against Taliban leader Mullah Akhtar Mohammad Mansour, the Pentagon said.
Pentagon press secretary Peter Cook said that the attack on Mansour took place "in a remote area of the Afghanistan-Pakistan border region".
A US official, speaking on condition of anonymity, said that President Barack Obama had authorised the operation, in which several drone aircraft had launched a strike on a vehicle in a remote area near Ahmad Wal, a town in western Pakistan.
The official said that Mansour, who emerged as the Taliban leader in 2015, was "likely killed".
Cook said that Mansour had presented a threat to US and Afghan forces and to local civilians.
"Mansour has been an obstacle to peace and reconciliation between the Government of Afghanistan and the Taliban, prohibiting Taliban leaders from participating in peace talks with the Afghan Government that could lead to an end to the conflict," Cook said.
In the last year, the Afghan Government has been struggling to contain a resurgent Taliban, which has shown itself to be a still-powerful force as foreign troops have departed.
The US official said that the results of the strike were still being examined but that it appeared a second man travelling with Mansour, described as another combatant, was also believed to have been killed.