A NATO air strike on Saturday killed at least two dozen militants in eastern Afghanistan, the military alliance's force in the country said.

The air strike, carried out with the approval of Afghan forces, came after the allies "observed a large group of insurgents in a remote area and engaged them," a spokesman for NATO's International Security Assistance Force told AFP.

"There are no civilian casualties," he added. "Afghan and foreign forces are currently conducting a follow-up assessment."

Taliban spokesman Zabiullah Mudjahid, speaking to AFP from an undisclosed location, confirmed the attack, saying 13 of the group's fighters were killed.

The militants had gathered to publicly execute a man accused of killing another man from a rival family a day before in Chapa Dara district of Kunar province, the district police chief Najibullah Gujar told AFP.

"Between 40 and 60 Taliban militants were killed in the air strike in Chapa Dara," he said.

"People had arrested the killer and the Taliban wanted to execute him in public."

But Mohammad Daud Zarba, deputy police chief of Kunar, told AFP the militants wanted to attack and take over the district. He said around 30 militants were killed in the attack.

Dost Mohammad, a witness in the area, told AFP that the burnt bodies of the Taliban were still on the ground.

"Out of around 80 Taliban who had come to settle the dispute only around 15 could escape the bombing," he said.

In some parts of the war-torn country where the government has no control, the Taliban operate a parallel government, with shadow governors and their own Sharia justice system.

Public executions of alleged murderers and adulterers were common when the Taliban regime was in power from 1996 until 2001, when they were ousted by a US-led invasion following the September 11 attacks.