DUBLIN (AP) — Northern Ireland's police commander says Irish Republican Army dissidents left a 400-pound (180-kilogram) car bomb outside the police-reform headquarters in Belfast but the homemade device failed to detonate.

Chief Constable Matt Baggott said Sunday that the abortive attack on the Northern Ireland Policing Board represented an attack on the province's entire peace process.

The explosives-laden car caught on fire but didn't explode and caused no damage to the building, where a joint Catholic-Protestant panel oversees police operations.

Also Sunday, detectives arrested three suspected IRA dissidents on suspicion of involvement in a gun attack on a police patrol in the Northern Ireland border village of Garrison. Baggott said police returned fire, but nobody was hit.