Baghdad, Sept 5 (SPA) - Up to 30 gunmen in 10 cars fired on Iraq's interior ministry at dawn on Monday, killing two police and wounding five, ministry sources said, in what appeared a carefully coordinated attack on a sensitive target. The attack came as campaigning was getting under way for a referendum due by Oct. 15 on a contentious new constitution for the post-Saddam Hussein era, and of the trial of Saddam himself, now confirmed for Oct. 19. "Two policemen were killed and five wounded," an Interior Ministry source told Reuters, adding that the gunmen, in 10 cars, had used rocket-propelled grenades, mortars and automatic rifles in the attack at 6:15 a.m. (0215 GMT). No other details were available. U.S. helicopters were circling low over the city center throughout the morning. --SPA 1131 Local Time 0831 GMT www.spa.gov.sa/287209