Reuters/U.S. Air Force/Bobbi Zapka/

Five Afghan soldiers have been killed in an airstrike by the NATO-led force in Afghanistan in eastern Logar province, according to a government official.

The reason for the airstrike on Thursday is not clear, Reuters quoted the provincial governor’s spokesman Din Mohammad Darwish as saying.

The NATO-led force in Afghanistan said it was aware of reports. However, it did not immediately provide any details.

Five Afghan soldiers have been killed and 17 people wounded in an airstrike by the NATO-led force in Afghanistan in eastern Logar province.

The airstrike, one of the deadliest friendly fire incidents in recent years, occurred at about 3:30 am local time and seriously wounded a further eight soldiers, bringing the total number of injured people to 17.

Dead bodies and wounded personnel have been transferred from the Chark district of Logar province to Kabul, the Afghan defense ministry said in a statement. It added that a delegation has already been sent to investigate.

Coalition forces operating in Afghanistan have said in a statement that the bombing was an accident, but did not give any further details of what might have been the cause of the deadly error.

“We value the strong relationship with our Afghan partners, and we will determine what actions will be taken to ensure incidents like this do not happen again,” the ISAF statement said, adding that they are conducting an investigation "to determine the circumstances that led to this unfortunate incident."

"Right now a discussion in the province is going on between Afghan officials and foreign forces to find out the reason for this attack," district governor Khalilullah Kamal said, adding that a new outpost of the Afghan army was targeted.

"The post is totally destroyed," he said. "The Americans used to be in that post but since they left, the ANA (Afghan national army) took over. The post is on a hilltop. The attack was conducted by drones."

Coalition airstrikes which lead to deaths among the civilian population and Afghan soldiers have created an ever widening rift between outgoing President Hamid Karzai and the United States to the point where he has refused to sign a bilateral security deal to allow US troops to remain in the country after 2014.

“We condemn the attack on the Afghan National Army in Logar. The president has ordered an investigation,” said Aimal Faizi, a spokesman for Karzai.

Previously Karzai had ordered an end to all NATO airstrikes in Afghanistan unless they were cleared first by the Afghan defense ministry. Karzai has also issued a decree banning airstrikes in residential areas.

All NATO forces are due to leave Afghanistan at the end of this year.