Two suicide bombers killed 30 people and wounded 65 others when they detonated explosive vests in a busy market in a town northeast of Baghdad on today.
Police said the second bomber struck as crowds rushed to evacuate the wounded from the first attack, a common tactic used by bombers to maximise casualties.
Iraq has seen a surge in violence over the past month, mainly involving clashes pitting Shia militias against US and government troops in Baghdad and the south.
But al-Qaeda has also struck with a number of large suicide bombings in the north. Iraqi government figures show April was the deadliest month for civilians since August last year.
Earlier, a car bomb aimed at a US patrol in Baghdad today killed at least nine Iraqi civilians and wounded 26. The US military claimed it killed 17 militants amid escalating fighting in the Shia slum Sadr City.
The explosion occurred about 9 am (local time) in a crowded commercial area in eastern Baghdad, police officials said, adding the nine killed included three women and a child.
The US military said no American soldiers were killed, although three were wounded in the attack.
Health officials also said clashes in Baghdad's Shia militia stronghold of Sadr City killed eight people, including two women and a child, and wounded 18 others, including women and children.
The Iraqi officials spoke on condition of anonymity because they weren't authorized to release the information.
Prime Minister Nouri al-Maliki has accused fighters of the anti-American cleric Muqtada al-Sadr's Mahdi Army of using residents as human shields during close combat in the teeming slum, which has become the epicenter of fighting since a government crackdown triggered clashes in late March.
In fighting late last night and early this morning in Sadr City, US soldiers killed 17 militants in a series of clashes. Several of the militants had fired on the military or were preparing to. Other militants were killed while planting a roadside bomb. The fighting was reported in statements issued today by the military.
A roadside bomb struck an Iraqi patrol car today, killing two Iraqi soldiers in the northern city of Mosul, police said.