At least 36 people were killed and more than 100 wounded in three apparently co-ordinated car bombs at two markets in Baghdad's Shia district of Sadr City today, police said.
It was one of the worst days of violence in the capital in recent months.
Two car bombs exploded in one market while a third blew up almost simultaneously at another. Police said they had found a fourth car bomb at a third market and defused it.
Sadr city is a stronghold of radical Shia cleric Moqtada al-Sadr, who commands the Mehdi Army militia force.
The district in eastern Baghdad has been relatively free of violence in the last couple of years.
Iraq has been gripped by a spasm of sectarian bloodletting following the bombing of an important Shia mosque in Samarra on February 22nd, sparking fears the country was sliding into civil war. But in recent days there had been a relative lull in the violence, prompting officials to declare the crisis was over.
Ten people were killed in a series of mortar blasts and roadside bombings in Baghdad earlier on Sunday and the trial of Saddam Hussein and seven co-accused on charges of crimes against humanity resumed after a 10-day break.