A local government official says gunmen have attacked Iraq's largest oil refinery, killing one guard and detonating bombs that sparked a fire and forced the facility to shut down.

The spokesman for Salahuddin province, Mohammed al-Asi, says the assailants broke into the Beiji refinery around 3:30 am, attacked the guards and planted bombs. One guard was killed and another wounded.

Firefighters were trying to put out a blaze started by the bomb explosions, the Associated Press reported.

The refinery processes about 150,000 barrels of oil per day. Beiji is about 155 miles (250 kilometers) north of Baghdad.