Attacks across Iraq, including more than a dozen car bombs, killed at least 46 people on Sunday while the head of Baghdad's provincial council escaped an assassination attempt on his convoy.

The violence was the latest in months of unrelenting bloodshed, the country's worst since 2008, that has sparked concern Iraq is slipping back into the all-out sectarian war of previous years that killed tens of thousands.

Authorities have imposed tough restrictions on movement in the capital and elsewhere, and carried out wide-ranging operations against militants, but insurgents have pressed their attacks.

On Sunday, they struck in more than a dozen towns and cities, with at least 17 car bombs, killing 46 people and wounding more than 130 overall.

The deadliest violence was in and around the city of Hilla, the predominantly Shiite capital of Babil province south of Baghdad, where four car bombs killed 19 people, police and medics said.

"I saw many people with burns, and people who were on fire, they were screaming for help," said Sajjad al-Amari, a 22-year-old witness to one car bombing on the outskirts of Hilla.

Another witness, Karrar Ahmed, told AFP he saw "many shop owners who were thrown to the floor, many were killed and wounded, and they were lying on the ground, among the goods from their shops".

Ahmed, still shaking with nerves, said incompetence by the security forces had "cleared the way for terrorists to target, and kill, civilians".

No group immediately claimed responsibility for the violence, which largely struck majority Shiite areas. Sunni militants linked to Al-Qaeda, however, often target Iraq's Shiite majority, whose adherents they regard as apostates.

In Baghdad, meanwhile, a car bomb hit the convoy of Riyadh al-Adhadh, chief of the provincial council and a Sunni lawmaker from the party of the national parliament speaker.

Adhadh was unharmed but two others, including one of his bodyguards, were killed and four people were wounded.

The blast shattered the windows of nearby shops and buildings, and security forces imposed a cordon around the area in the aftermath, an AFP journalist at the scene said.

A separate car bomb later on Sunday in the capital killed three others.

Another car bombing at a market on the outskirts of the southern port city of Basra killed three people and wounded 15 others, officials said.

Attacks south of Baghdad -- in Yusifiyah, Karbala, Nasiriyah, Kut, Suweirah and Hafriyah -- left nine people dead, while shootings and bombings in and around the northern and western cities of Abu Ghraib, Baquba, Sharqat, Kirkuk and Mosul killed 10 more.

The latest bloodshed comes amid a months-long increase in violence which has left more than 4,000 dead already this year, as Iraq grapples with a prolonged political deadlock and spillover from the civil war in neighbouring Syria.

On Saturday, a suicide bomber at a funeral near Mosul, Iraq's main northern city, killed 27 people and wounded dozens, and violence in the past week alone has claimed more than 200 lives.

Authorities insist a campaign targeting militants is yielding results, claiming to have captured hundreds of alleged fighters and killed dozens, with security forces apparently having dismantled several insurgent training camps and bomb-making sites.

But the government has faced criticism for not doing more to defuse Sunni Arab anger over alleged ill-treatment at the hands of the Shiite-led authorities.

Analysts and diplomats say militants have exploited this on the ground to recruit new fighters and carry out attacks.

Last week, an Al-Qaeda front group claimed responsibility for a spate of car bombs that targeted Shiite neighbourhoods of Baghdad and left 50 dead.

The surge in violence comes as the government grapples with a prolonged political stalemate, with no significant legislation passed since March 2010 parliamentary elections.