Nato has admitted that it killed Afghan civilians when battling the Taliban in the east of the country.

The undetermined number of deaths occurred on Thursday in the Shirzad district of Nangarhar province. Nato's International Security Assistance Force (Isaf) promised in a statement that the families of the victims would be compensated.

"Following information received from provincial and local Nangarhar officials, it appears that between four and a dozen or more civilians were killed," the statement said.

Hamid Karzai, Afghanistan's president, has ordered a probe into the death of at least 12 civilians after a district chief said a total of 26 people had been killed in two separate incidents in the area.

Al Jazeera's James Bays, reporting from Kabul, the capital, said that the deaths were caused by an air raid.

"There have been civilians that were killed in what Isaf is admitting is an air strike carried out by their aircraft. They say they are investigating the incident."