BAGHDAD (Reuters) - Seven bombs exploded across Baghdad on Wednesday, killing 23 people and wounding scores, police and medical sources said, part of the worst wave of violence to hit Iraq in at least five years.

The Shi'ite-led government has blamed Sunni Muslim insurgents linked to al-Qaeda for the increased bomb attacks, which have mainly targeted Shi'ite civilians.

The explosions early on Wednesday took place as people shopped in crowded markets.

Among the most deadly, a roadside bomb near a market in the mainly Shi'ite neighborhood of Sadriya killed four and wounded 14, while a bomb in a minibus in the central commercial district of Karrada, killed 3 and wounded 12.

Black smoke billowed from the scene of the explosion on a main road in Karrada where ambulances weaved through the traffic to reach the wounded, video footage showed. The minibus was shown with its main door blown off and shattered windows.

Hundreds of Iraqis have been killed each month in similar attacks since the start of the year. The growing violence has raised fears of a return to the heights of bloodshed seen in 2006-2007, when tens of thousands died.

Nearly 1,000 Iraqis were killed in October, according to figures from the United Nations, which has called on political leaders to cooperate to end the violence that has escalated since U.S. troops withdrew in December 2011.

Elsewhere in Iraq on Wednesday, gunmen killed an off-duty bodyguard of President Jalal Talabani. The gunmen broke into the bodyguard's house in Sulaimaniya, 260 km (160 miles) northeast of Baghdad. Talabani has been in Germany for medical treatment for several months.

(Reporting by Kareem Raheem and Ahmed Rasheed, Writing by Sylvia Westall; Editing by Janet Lawrence)