Mortar fire, car bombs and gunfire killed at least 14 people and wounded 55 in Baghdad on Saturday, police and medics said.
After a relatively calm day, a series of explosions shook the Iraqi capital in the evening as unidentified assailants set off at least four car bombs and fired several mortar rounds.
Armed men also attacked a juvenile prison, killing a guard, wounding four and releasing 20 inmates, police said.
In Baquba, 65 km (40 miles) northeast of Baghdad, gunmen badly wounded a correspondent of the opposition Sharqiya TV channel. There was no word on the motive for the attack.
Helicopters hovered over some areas of Baghdad after the blasts as ambulance sirens wailed and security forces closed some roads, residents said.
Two years after U.S. troops left Iraq, violence has climbed back to its highest levels since the Sunni-Shi'ite bloodletting of 2006-2007, when tens of thousands of people were killed.
The United Nations says nearly 9,000 people died violently in Iraq last year, all but 1,050 of them civilians.
Tension has been high this year since al Qaeda-linked militants and other Sunni Muslim insurgents seized the city of Falluja west of Baghdad on Jan. 1, exploiting grievances among minority Sunnis over the actions of the Shi'ite-led government.