Suspected Sunni insurgents penetrated the Baghdad security net Wednesday, hitting Shiite targets with four bomb attacks that killed 183 people - the bloodiest day since the U.S. troop surge began nine weeks ago.
Late Wednesday, Prime Minister Nouri al-Maliki ordered the arrest of the Iraqi army colonel who was in charge of security in the area around the Sadriyah market where at least 127 people died and 148 were wounded in the deadliest bombing of the day.
Is the surge working?