KABUL-- Five Afghan soldiers were killed in a NATO airstrike in Afghanistan's eastern province of Logar on Thursday, Afghan officials and the coalition said.
The U.S.-led forces said the incident was an accident.
"We condemn the attack on the Afghan National Army," said a spokesman for the country's leader, Hamid Karzai. "The president has ordered an investigation."
Eight more were injured in the bombing, according to Afghan Maj. Gen. Zahir Azimi, who said there were no coordinated operations in the area near the Afghan National Army (ANA) outpost in the southeastern Logar province.
“A high level team has been sent to investigate the incident,” he said, adding that the bombardment took place at around 3:30 a.m. local time (5:30 p.m. ET Wednesday).
NATO's International Security Assistance Force (ISAF) said an investigation had been launched “to determine the circumstances that led to this unfortunate incident.”
“Our condolences go out to the families of the Afghan National Army soldiers who lost their lives and were wounded,” the coalition said in a statement. “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."
"We can confirm that at least five Afghan National Army personnel were accidentally killed this morning during an operation in eastern Afghanistan,” it added.
The deaths are sure to strain already tense U.S.-Afghanistan ties, which have worsened recently as Karzai refuses to sign a security deal that would allow American troops to remain in the country after the large-scale withdrawal of international forces this year. Coalition airstrikes on friendly targets widen the rift.
Henry Austin reported from London. Reuters contributed to this report.