At least 20 people were killed Sunday in a series of car bombings in the Iraqi capital Baghdad, said security officials.

The attacks in mainly Shiite areas in the centre and north of Baghdad injured at least 78, reported the independent website Alsumaria News, quoting the officials.

Iraq has witnessed near-daily attacks since US troops withdrew in December 2011, raising fears of a return to the sectarian tensions that drove the country close to civil war in 2006 and 2007.

The violence comes amid a widening crisis between the Shiite-led government and the Sunni minority.

Thousands of Sunni protesters have been rallying for two months against Shiite Prime Minister Nuri al-Maliki, demanding a repeal of laws they say marginalize Sunnis.

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