Twin bomb blasts in the southern Iraqi city of Kut killed 34 people on Monday, the worst of a spate of nationwide violence that left 47 dead, just months ahead of a pullout of US forces.
The surge of attacks in 10 cities, which left more than 160 people wounded, raise major questions over the capabilities of Iraq's security forces after the country's leaders agreed to open talks with Washington over a military training mission to last beyond a projected year-end American withdrawal.
The violence was quickly condemned by parliament speaker Osama al-Nujaifi, who blamed security leaders for unspecified "violations."
In Monday's deadliest attack, the bloodiest since July, a roadside bomb in the centre of Kut at 8:00 am (0500 GMT) was followed minutes later by a nearby car bomb, medical and security officials said.
"I was on my way to my shop in the market and sudden I felt myself being thrown to the ground," said 26-year-old Saadun Muftin, speaking from the city's Karama hospital.
"After that I found myself in the hospital with wounds all over my body."
Another shopkeeper, Mohammed Jassim, described "smoke everywhere" in the square where the blasts took place.
Karama hospital director Jabbar al-Yasiri put the toll at 34 dead and 64 wounded, with both figures including women and children. Security officials cordoned off the site of the attacks in their aftermath.
The violence was the worst in Kut, 160 kilometres (100 miles) south of Baghdad, since August 3, 2010, when two car bombs killed 33 people, and the single deadliest in Iraq since July 5 this year, when twin suicide blasts killed 35 just outside Baghdad.
In Saddam Hussein's hometown of Tikrit, meanwhile, three policemen were killed and at least seven others were wounded when two suicide bombers blew up their explosives-packed vests inside the city's anti-terror headquarters.
"They managed to enter wearing police uniforms and using fake IDs, passing three checkpoints," said a security official, speaking on condition of anonymity. He said among those killed in the attack were Salaheddin province's deputy anti-terror chief.
"They were trying to free Al-Qaeda fighters from the anti-terror department's jail."
And in the restive central city of Baquba, north of the capital, four soldiers were gunned down at an Iraqi army checkpoint, according to an official in the provincial security command centre.
Three other bomb blasts in Baquba and a town to its south left 31 wounded, the official said, adding that the provincial government offices have been evacuated.
Two car bombs, one of them detonated by a suicide attacker, also killed two people and wounded 20 others in the holy Shiite city of Najaf in south Iraq, according to provincial police chief General Abdul Karim Mustafa and a doctor.
A car bomb east of Karbala, another holy city in Iraq's south, killed two and wounded nine others, according to provincial council chief Mohammed al-Mussawi.
Separate explosions in the disputed northern city of Kirkuk killed one and wounded 14, while twin blasts in the western city of Ramadi left one dead and injured seven others.
A car bomb in west Baghdad and a roadside bomb in a town on the capital's outskirts wounded a total of 10 others, security officials said.
The attacks come after Iraqi leaders said on August 3 they would hold talks with the US over a security training mission to last beyond 2011, when all 47,000 American soldiers must withdraw under the terms of a 2008 bilateral security pact.
Violence in Iraq has declined from its peak in 2006 and 2007, but attacks remain common. A total of 259 Iraqis were killed in attacks in July, the second-highest figure for 2011.