Twenty people were also wounded in the violence, the latest in a surge of killings in August and as Muslims observe the holy fasting month of Ramadan, when insurgents typically step up their attacks, fuelling security concerns as the United States continues to withdraw its troops.
In a pre-dawn attack, three Sunni Muslims were gunned down as they exited the Abid Wais mosque in Jurf al-Sakhr, 50 kilometres (30 miles) south of the capital in Babil province, police said.
The drive-by shooting, which also left one person wounded, took place at 4:00 am (0100 GMT), after worshippers completed Ramadan prayers which followed a communal meal ahead of a day-long fast.
Jurf al-Sakhr lies within a confessionally mixed region known as the Triangle of Death because of the frequency of insurgent attacks during the worst of Iraq’s violence following the 2003 US-led invasion.
Three others, including an off-duty policeman, were killed when the minibus they were on was struck by a bomb attack as it travelled to the centre of Baghdad from its eastern quarter, an interior ministry official said.
He added that 11 people, including three women, were wounded.
A traffic policeman and a civilian were also killed, and a police officer was wounded, when a roadside bomb exploded near Al-Shaab stadium in the east of the capital, a doctor at Ibn Nafis hospital said.
A ninth person was killed and seven others wounded by three roadside bombs in northern Baghdad, interior and defence ministry officials said.
The latest unrest, in which well over 100 people have been killed so far this month, has fuelled concerns about security as the United States pulls out thousands of troops from Iraq, although US officers insist Iraqi soldiers and police are up to the task of replacing them.
Iraq is also grappling with a five-month-long political impasse after a March 7 parliamentary election failed to produce a new government.
City have now conceded eight goals in their last three Premier League games
Hruncakova and Snigur in fine form as Gulf region's oldest tournament for women opens