A suicide attack has injured four German soldiers in Afghanistan’s northern Kunduz province.The blast comes the day after a NATO airstrike there killed up to 90 people, many of them civilians. Survivors have told how they were collecting fuel from tankers bombed by a US warplane. Permission to fire was granted by a German commander on the ground. It is feared the strike could trigger a major backlash against NATO, which says its targets were Taliban fighters who had hijacked the fuel trucks. “We have suffered enough over three decades of war,” said one resident of Kunduz. “Now we want to have a peaceful future. But yesterday’s incident has worried people a lot and we are wondering what to do and where to go.” Amid fears Friday’s bombing could reignite Afghan outrage against foreign troops, there is tight security on the streets. NATO meanwhile has ordered an inquiry into what went wrong.