Baghdad, Rabi Al-Awwal 23, 1432, SPA -- Four engineers were killed when gunmen attacked Iraq's largest oil refinery, state TV reported Saturday. The attack completely halted work of the refinery, located in the northern town of Beiji, after gunmen destroyed three production units. Security forces have imposed a curfew on the town of Beiji, according to a report of DPA. --SPA 14:46 LOCAL TIME 11:46 GMT www.spa.gov.sa/868278