A NATO air raid in eastern Afghanistan has accidentally killed five Afghan soldiers, officials say.

NATO offered its condolences for Thursday's deaths and pledged action to avoid further mistakes, but President Hamid Karzai has often seized on botched raids to launch bitter criticism of the international military effort in Afghanistan.

"At 3:30am this morning, due to a NATO air strike in Charkh district, Logar province, five service members of the Afghan national army were martyred and eight others were wounded," Zahir Azimi, Afghanistan's Defence Ministry spokesman, said on his Twitter account.

Khalilullah Kamal, Charkh district governor, told AFP news agency he had visited the site of the attack, which he said was from a US drone.

"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."

NATO's International Security Assistance Force (ISAF) issued a statement confirming that at least five Afghan soldiers had been killed accidentally.

"An investigation is being conducted at this time to determine the circumstances that led to this unfortunate incident," it said.

"Our condolences go out to the families of the ANA soldiers who lost their lives and were wounded ... we will determine what actions will be taken to ensure incidents like this do not happen again."

An ISAF source told Reuters news agency that the soldiers were bombed because they were mistaken for insurgents.

"The aircraft engaged suspected insurgents on a ridge overlooking Nawer village," the source said, adding that the victims were later identified as soldiers.

READ MORE: NATO air raid kills Afghan soldiers