Attacks in Baghdad and northern Iraq on Sunday killed seven people, including four policemen, and wounded 16 others, officials said. Near the main northern city of Mosul, a car bomb exploded as security forces searched a home, killing three policemen and wounding 15 people, police and medical sources said. Gunmen killed a fourth policemen inside the city. And in north Baghdad, gunmen opened fire on a group of civilians, killing three and wounding one. Iraq is struggling to contain a wave of violence that has killed more than 430 people so far this month -- the second month in a row in which more than 400 people have died in unrest. Violence in Iraq has decreased from its peak in 2006 and 2007, but attacks remain common, killing at least 200 people each month so far this year.