A suicide car bomb exploded Wednesday at an Iraqi police checkpoint guarding a courthouse in Ramadi, killing at least six people in the largest attack on Anbar province's capital in months, AP quoted police sources as saying. The dead included three women, said Col. Jubair Rashid Naief, a provincial police official. Another 13 people were wounded, he said. Ramadi, 115 kilometers (70 miles) west of Baghdad, was once a base for Sunni insurgents, but has seen a huge security improvement since many Sunni tribesmen began partnering with U.S. forces last year. Wednesday's suicide blast was the largest such attack in Ramadi in months.