A NATO airstrike Wednesday mistakenly hit an Afghan army unit in southern Afghanistan, killing five soldiers, a Defence Ministry spokesman said.
The soldiers were conducting an anti-insurgent operation in Andar district of Ghazni province on early Wednesday, General Zahir Azimi told a press conference, DPA reported.
A plane of the NATO-led International Security Assistance Force (ISAF) targeted the unit, killing five soldiers and injuring two others, Azimi said.
"It is not the first time. It has happened several times in the past, but we hope that this should be the last time," he said.
ISAF spokesman General Joseph Blotz said a lack of coordination between foreign troops and Afghan soldiers on the ground could have been the reason for the mistake.
"What we know so far is, yes, indeed ANA (Afghan National Army) troops have been attacked by ISAF," he said. "I do clearly regret what has happened."
A joint investigation by Afghan and NATO officials was under way, Blotz said.