Bonn Bomb As Big As Madrid Devices

The area was sealed and the device was destroyed with a water cannon - which may have broken the detonator into "countless pieces," prosecutors said.

But authorities said that if the explosive had been detonated, it could have had a similar effect to the 2004 al-Qaida bombing in Madrid, which killed 191 people.

"It was an extremely dangerous explosive device," state prosecutor Rainer Griesbaum said on Wednesday.