Germany's Labour Minister Franz Josef Jung has resigned from the cabinet amid allegations of a cover-up relating to the NATO bombing of two oil tankers in Afghanistan.

Mr Jung was defence minister when a strike was ordered on 4 September by a German commander on the fuel tankers, which had been hijacked by Taliban militants in the province of Kunduz. Dozens of civilians were also killed in the attack, but Mr Jung insisted for several days that only "Taliban terrorists" were among the dead.

A confidential NATO report in October said the death toll varied between 17 and 142 and local sources had said between 30 and 40 civilians died. An independent Afghan rights group puts the civilian death toll at over 70. Mr Jung's position was weakened after claims that the defence ministry hushed up another report on civilian casualties, which suggested that commanders on the ground did not adhere to the agreed rules of engagement.

After army chief of staff General Wolfgang Schneiderhan stepped down on Thursday, followed by Deputy Defence Minister Peter Wichert, pressure was mounting on Minister Jung. The German newspaper, Bild, said they showed that the German commander who ordered the strike, Georg Klein, had not been able to rule out the presence of civilians before he took action. The justice ministry is investigating whether to instigate proceedings against Mr Klein.

Germany has more than 4000 troops stationed in Afghanistan, the third largest contingent after the US and Britain.