Baghdad - A wave of car bombs ripped through Shi'ite areas of Baghdad on Tuesday, the deadliest attacks in nationwide violence that killed more than 40 people as Iraq grapples with surging unrest.
The bloodshed added to widespread concern that Iraq is edging towards a return to the all-out sectarian war that left tens of thousands dead in 2006-2007, amid a long-running political deadlock and persistent concerns of spillover from the conflict in neighbouring Syria.
Iraqi officials have trumpeted wide-ranging operations targeting militants in which hundreds of alleged fighters have been captured and dozens killed, despite charges of failing to address root causes of the violence.
Eight car bombs went off in predominantly-Shi'ite neighbourhoods of Baghdad on Tuesday, killing at least 34 people and leaving more than 80 others wounded, according to security and medical officials.
The blasts went off at around 18:00, the latest in a trend of attacks timed to coincide with Baghdad residents visiting cafes and other public areas during the evening.
In previous months and years, deadly coordinated violence has typically been confined to the morning rush-hour when the capital is normally in gridlock.
No group immediately claimed responsibility for the latest bloodshed but Sunni militants linked to Al-Qaeda frequently carry out coordinated attacks targeting Iraq's Shi'ite Muslim majority who they regard as apostates.
Nine other people were killed in attacks earlier the same day, officials said.
In the morning, gunmen entered the home of a Sunni Arab militiaman in south Baghdad and killed him, his wife, two sons and a daughter.
That came a day after two sets of attacks against the Sunni militia killed 12 people, including a coordinated assault involving two suicide bombers and a car bomb on the home of the militia's national chief in which he was wounded.
From late 2006 onwards, Sunni tribal militias, known as the Sahwa, turned against their co-religionists in al-Qaeda and sided with the US military, helping to turn the tide of Iraq's bloody insurgency.
But Sunni militants view them as traitors and frequently target them.
Also on Tuesday, two Shi'ite Muslim men were shot dead outside their homes in south Baghdad, while a policeman was killed by a roadside bomb in the predominantly Sunni northern city of Mosul.
Attacks have killed more than 3 800 people since the start of the year, according to an AFP tally.
Officials have vowed to press on with a campaign targeting militants that Prime Minister Nuri al-Maliki says has captured 800 alleged fighters and killed dozens of others, as well as dismantling training camps and bomb-making sites.
But the government has faced criticism for not doing more to tackle anger in the Sunni Arab community over alleged ill-treatment at the hands of Iraq's Shi'ite-led authorities.
Analysts and diplomats say this has given militant groups room on the ground to recruit and carry out attacks.