A wave of attacks, most of them car bombs targeting Shiite neighbourhoods, rocked Baghdad early on Wednesday, killing at least 24 people in the latest bout of bloodshed to rock Iraq.

The violence, which left 65 others wounded, comes amid a protracted surge in violence just months ahead of general elections that has forced Iraqi officials to appeal for international help in combatting the country's worst unrest since 2008.

At least seven explosions, including six car bombs, hit Shiite Muslim neighbourhoods of the Iraqi capital, according to security and medical officials, from about 7:30 am (0430 GMT) onwards.

They come after similarly coordinated bombings in Baghdad on Sunday evening left 21 dead.

Wednesday's attacks occurred in areas ranging from the city's main commercial district of Karrada to the predominantly Shiite neighbourhood of Shaab, as well as Sadriyah, one of Baghdad's oldest areas.

One car bomb also went off in the Sunni-majority neighbourhood of Adhamiyah in north Baghdad, the officials said.

Security forces imposed tough measures in areas hit by attacks, in many cases barring journalists from filming video or taking photographs at bombing sites.

No group immediately claimed responsibility for the violence, but Sunni militants linked to Al-Qaeda's front group often set off coordinated bombings across Baghdad, typically targeting Shiites, whom they regard as apostates.

The unrest is part of a surge in bloodshed that has pushed violence to its highest level since 2008, when Iraq was recovering from the worst of its Sunni-Shiite sectarian war.

Prime Minister Nuri al-Maliki has called for Washington's help in the form of greater intelligence sharing and the timely delivery of new weapons systems in an effort to curb the bloodshed.

But diplomats and analysts say the government is not doing enough to address the root causes of the unrest, particularly frustration in Iraq's Sunni Arab minority which alleges it is mistreated at the hands of the Shiite-led authorities.

And with elections due on April 30, officials fear the level of violence could rise further as militants seek to destabilise the country ahead of landmark polls.

In addition to failing to stem the bloodshed, authorities have also struggled to provide adequate basic services such as electricity and clean water, and corruption is widespread.

Political squabbling has paralysed the government, while parliament has passed almost no major legislation in years.