A string of bombings targeting Shia mosques in Iraq has killed at least 23 people and wounded dozens on Friday, officials said. The attacks were the latest in assaults staged by insurgents seeking to undermine the Shia-led government's efforts to achieve security across the country.

There was no immediate claim of responsibility, but the bombings bore the hallmarks of al-Qaeda's Iraq branch. The group, known as the Islamic State of Iraq, frequently uses car bombs, suicide bombers and co-ordinated blasts in an effort to sow fear among Shias and erode their trust in the government of Prime Minister Nouri al-Maliki.

Four car bombs hit Shia mosques in the Iraqi capital as worshippers were leaving after Friday prayers, killing 19 people and wounding 72.

First, a parked car exploded in Baghdad's western Jihad neighbourhood, killing seven worshippers and wounding 25, a police officer said. Another police officer said four people were killed and nearly 20 were wounded in a bombing in eastern Qahira neighbourhood. Three people died and 15 were wounded in the eastern Zafaraniyah district while yet another car bomb killed five people and wounded 14 in the northeastern Binook neighbourhood.

Three health officials confirmed the causalty figures. All officials in Baghdad spoke on condition of anonymity because they were not allowed to talk to the media.

And in the northern city of Kirkuk, 290 kilometres north of Baghdad, a suicide bomber drove his explosive-laden car into a group of worshippers as they were leaving a mosque after Friday prayers, killing three people and wounding up to 70, according to police Col. Najat Hassan. A senior provisional health official, Sidiq Omar Rasool, confirmed the casualty figures in Kirkuk.

Violence has ebbed sharply since the peak of Sunni-Shia fighting that pushed the country to the brink of civil war in 2006 and 2007, but Sunni insurgents still occasionally carry out high-profile attacks against Shias, considering them to be heretics.

Friday is a particularly popular day for militants to undertake such attacks because of the rush of mostly men and boys who flock to the mosques throughout the country to hear traditional Muslim sermons and take part in communal prayers.