A series of co-ordinated car bombs and explosions have rocked Shia districts across Baghdad and south of the Iraqi capital, killing dozens of people on the 10th anniversary of the US-led invasion.

Police officials say the attacks, mostly car bombings, targeted mainly small restaurants, groups of labourers and bus stops in the Iraqi capital, all within a one-hour period.

Officials say at least 34 people have been killed, with some reports claiming up to 50 dead. It is thought as many as 160 people have been injured.

A total of nine car bombs and roadside blasts went off across the capital on Tuesday. A suicide bomber driving a truck also attacked a police base in another predominantly Shia town south of Baghdad, police and hospital sources said.

No group immediately claimed responsibility.

Police officials said the first attack took place near a small restaurant in Baghdad's Mashtal district, killing four people and wounding 15. Minutes later, two labourers were killed and eight wounded when a roadside bomb went off where they gather each day in partof New Baghdad.

In the neighbourhood of Sadr City, a sticky bomb attached to the underside of a minibus killed three commuters and wounded seven people. Another car bomb exploded in a commercial street in the same Shia area, killing two people and wounding 11.

"I was driving my taxi and suddenly I felt my car rocked. Smoke was all around. I saw two bodies on the ground. People were running and shouting everywhere," said Al Radi, a taxi driver caught in one of the blasts.

In the north-eastern suburbs of Baghdad, four people were killed and 11 others wounded after a car bomb went off near a small restaurant in Hussainiyah.

In Zafaraniyah, two car bombs exploded near a police station, killing five people, including a policeman and wounding 27, said police. In northern Baghdad, a car bomb went off near a bus stop, killing three people and wounding 13.

In central Baghdad, a car bomb exploded near a restaurant not far away from the well-protected green zone, killing six people, including two soldiers and wounding more than 15. In Shulla, a car bomb exploded near an outdoor market, killing five people and wounding 21.

Although no group claimed responsibility for Tuesaday's attacks, Iraq's al-Qaida wing, the so-called Islamic State of Iraq, has vowed to take back ground lost in its long war with the US-led coalition. Since the start of the year the group has carried out a string of high-profile attacks, including the storming of the well-protected Justice Ministry building in central Baghdad on Thursday, killing 25 people.