Fighting in northern Iraq killed nine police Friday, while a car bomb targeting worshippers near a Sunni mosque north of Baghdad left four dead, security and medical officials said.

The fighting between police and armed men in west Mosul, including mortar rounds fired at checkpoints, killed nine police and wounded seven, police and a doctor said.

Four gunmen were also killed in the clashes.

In Rashidiyah, north of Baghdad, the car bomb exploded as worshippers left Friday prayers at Al-Ghufran mosque, killing at least four people and wounding 22, an interior ministry official and a medical source said.

And in Al-Amil in south Baghdad, a magnetic "sticky bomb" wounded a police captain, while a roadside bomb wounded three more police in Taji, north of the capital, the ministry official and medical sources said.

The violence came a day after the United Nations said April was the deadliest month for Iraq in almost five years.

While violence has fallen from its peak at the height of the sectarian conflict in Iraq in 2006 and 2007, attacks remain common.