“According to our information, the report clearly points to errors in the way the operation was carried out by the Germans,” the usually well-informed German weekly said in its edition to be published on Monday.

The September bombing targeted two fuel tankers that German forces said were hijacked by Taliban insurgents and represented a danger. In the immediate aftermath, Berlin said around 50 militants were killed in the attack and no civilians.

Witnesses however spoke of several civilian casualties, prompting critical reactions even from Germany’s own NATO allies.

General Wolfgang Schneiderhan, general inspector of the German army, said on Thursday that according to the report the commander, Colonel Georg Klein, had acted correctly in ordering the strike.

“In light of the results of the report, I have no reason to doubt that German soldiers acted in the correct military fashion, given their mandate from the United Nations and the difficult operational situation,” Schneiderhan said.

He said the exact death toll in the attack could no longer be determined, adding that the report cited a range of between 17 and 142 casualties.

Der Spiegel quoted an official familiar with the report as saying the NATO report “gives as many reasons to condemn (Colonel Klein) as to clear him.”

The magazine said that Klein did not respect procedures as he had justified his call for an attack by saying his troops were in direct contact with insurgents, which was not the case.

The German government further tried to put pressure on NATO for the report’s conclusions not to be too hard on Klein, Der Spiegel said.

This message was given to NATO commander in Europe Admiral James Stavridis during a visit to Berlin on October 15.

Germany has around 4,200 troops in an increasingly unpopular mission in Afghanistan facing an ever more tenacious insurgency.