A bomb blew up at a British Army barracks in Duesseldorf Friday, injuring three soldiers and a civilian and tearing off part of the roof, a military spokesman said.

British Army spokesman Colin Tavner told The Associated Press that all of the injured were treated for cuts and bruises and then released. He said no arrests had been made but West German police were investigating.There was no immediate claim of responsibility, but a spokesman for the federal prosecutor said the Irish Republican Army was suspected.

"The time and the target of the bombing indicate that the IRA may have been involved," said the spokesman, Hans-Juergen Foerster. He said the federal prosecutor's office, which usually investigates terrorist attacks, had taken over the inquiry.

The state government of North Rhine-Westphalia said five people, not four, were injured in the attack on the Roy Barracks, in the western part of the country.

"Political motives are suspected," said Luediger Harmeier, a spokesman for the state Interior Ministry.