At least 80 people have been killed and more than 250 others wounded in a series of bombings and other attacks across Baghdad, police and medical sources said.
The northern neighbourhood of Kadhimiyah, home to a prominent, gold-domed Shia shrine, was the worst hit.
Two bombs went off in a parking lot, followed by a suicide car bomber who struck onlookers who had gathered at the scene. Police said 10 people were killed and 27 wounded in that attack.
In Sadr City, an impoverished Shia district in Baghdad's northeast, two car bombs killed seven people. A restaurant owner said he saw an attacker just before one of the explosions.
"A man parked his car in front of the restaurant. He got breakfast and drank his tea. Then I heard a huge explosion when I was inside the kitchen," the owner, who requested anonymity, told the Reuters news agency.
"When I went outside, I saw his car completely destroyed and he had disappeared. Many people were hurt."
Another car bomb killed seven people and wounded 23 in Jisr Diyala in southeastern Baghdad, police and medics said.
The Interior Ministry described the attacks as "terrorist explosions" but said the number of people killed was only 20, with 213 wounded. Baghdad has said that media reports exaggerate attacks in Iraq, and that security forces have stopped many attempted bombings.
Police and militias targeted
More than 1,000 Iraqis were killed in July, the highest monthly death toll since 2008, according to the United Nations.
When I went outside, I saw his car completely destroyed and he had disappeared. Many people were hurt.
The renewed violence, 18 months after US troops withdrew from Iraq, has stirred anxiety about a relapse towards the widespread sectarian slaughter of 2006-07.
In other attacks on Wednesday, gunmen killed six members of the Sahwa, ("Awakening") movement, a group of former Sunni fighters who rebelled against al-Qaeda. They were attacked in an ambush on a checkpoint in Latifiya, a suburb 40km south of Baghdad.
Armed men also stormed a Shia home in the same area, killing six family members, police and medical sources said.
Four soldiers were killed and five were wounded in Madaen, southeast of Baghdad, by a roadside bomb targeting an Iraqi army patrol, police and medics said.
After years of reduced violence, the intensity of attacks has dramatically risen since the start of 2013.
Bombings have often targeted cafes and other places where families gather, as well as military facilities and checkpoints.