BAGHDAD, Iraq — Bombs killed more than 60 people and wounded more than 200 Sunday in Baghdad and the northern oil center of Kirkuk — a dramatic escalation of violence as U.S. and Iraqi forces crack down on Iraq's most feared Shiite militia.

Prime Minister Nouri al-Maliki left Sunday for talks in Washington this week with President Bush to discuss sectarian violence.

A suicide driver detonated a minivan at the entrance to a bustling market in Sadr City, the capital's biggest Shiite district and stronghold of radical cleric Muqtada al-Sadr and his Mahdi Army militia. At least 34 people were killed and 74 were wounded, the Iraqi army said in a statement.

Eight more people died and about 20 were injured when a roadside bomb exploded two hours later at a municipal building in Sadr City about a half mile from the car bombing, the army said.

In Kirkuk, 180 miles to the north, a car bomb detonated at midday near a courthouse. Twenty people were killed and 159 were wounded, police said.