NATO is launching an investigation into the allegedly accidental killing of six Afghan soldiers on Friday by German troops.
It came hours after the Germans lost three of their own in an ambush by Taliban insurgents in the northern Kunduz province.
NATO said the German unit was on its way to the scene of the fierce gunbattle during which five other troops were seriously wounded.
The soldiers allegedly opened fire on two unmarked civilian vehicles that failed to stop.
Issuing an apology, NATO Brigadier General Eric Tremblay said: “We regret this tragic loss of life. We will try and strive to improve our tactics, techniques and procedures.”
Germany is the second largest European contingent in Afghanistan behind Britain. The Bundestag, Germany’s parliament, recently approved the deployment of 850 reinforcements.
But its military presence has been controversial back home, especially since almost 150 Afghan civilians were killed last September when German commanders ordered an airstrike on a fuel tanker hijacked by suspected Taliban militants.