Police in Heidelberg, Germany, shot and seriously injured a man Saturday after the man hit three people with a car.

The man drove his car into the people in a central square while they were standing in a pedestrian area. A brief stand-off ensued before police shot the man, who was believed to have been armed with a knife.

Police said that at the moment they are unclear about the man’s motives but added they don’t suspect the attack to be terrorism-related.

The man appears to have acted alone, police said, refusing to confirm local media reports he is mentally disturbed.

The incident renewed fears in Germany of an attempted repeat of a terrorist truck attack last December at a crowded Berlin Christmas market that killed 12 people and injuring 50 more.