Iraqi police say three suicide bombers have stormed a police battalion headquarters in the city of Mosul, killing four police including a commander.
A fourth suicide bomber was reportedly killed by police before he was able to enter the main building.
The slain commander had escaped five previous assassination attempts.
An Al-Qaeda-linked group known as the Islamic State of Iraq has claimed responsibility for the attack, which comes two days after suicide bombers killed 17 people and wounded dozens in a raid on a government building in the western city of Ramadi.
compiled from agency reports