Mayor Adolf Sauerland said that until the investigation was complete, any aportioning of guilt would be "out of place, our of order".
"That would not serve the victims, nor would it serve the families," he said.
He said 340 people had been injured.
Sixteen of the dead had been identified, he added, and four of the victims were foreigners: one from the Netherlands, one from Australia, one from Italy and one China. They ranged in age from just over 20 to 40.