Shootings and a bombing killed seven people in Iraq on Tuesday, officials said, as Prime Minister Nuri al-Maliki condemned attacks on mosques he said were aimed at promoting sectarian strife.

In the northern city of Mosul, a magnetic "sticky bomb" exploded on a provincial councillor's car, killing her driver but leaving her unharmed, while gunmen killed a policeman in the centre of the city, security and medical officials said.

In the Bayaa area of Baghdad, gunmen armed with silenced weapons killed two people, while gunmen killed a police officer in another attack in Fallujah, west of the capital, sources said.

And near Baquba, north of Baghdad, gunmen killed a man who ran with Maliki's State of Law coalition in provincial polls last month, along with a policeman who was travelling in the car with him.

Maliki said in an online statement that security has been stepped up at Sunni mosques and Shiite places of worship, called husseiniyahs.

Both have been targeted in recent weeks, but most of the attacks have been against mosques or worshippers who were leaving them.

As part of a "plan to stir sectarian strife, specific areas, mosques and husseiniyahs are being targeted here or there by terrorist forces and extremist groups," Maliki said.

He said security at places of worship has been stepped up, and also called on officials to stop issuing inflammatory statements and work to promote national unity instead.

Security forces moved against anti-government protesters in northern Iraq on April 23, sparking clashes in which 53 people were killed, while dozens more died in subsequent violence, including revenge attacks on security forces.

The wave of unrest, which killed more than 200 people, raised fears of a return to sectarian conflict that plagued Iraq from 2006 to 2008.

With the Tuesday attacks, 71 people have been killed in violence so far this month, more than a third of them police, according to AFP figures based on security and medical sources.