Violence in Iraq killed 29 people Saturday, most of them militants who died in a security forces assault that pushed them out of an area west of Baghdad, officials said.

Anti-government fighters have held shifting parts of Anbar provincial capital Ramadi and all of the city of Fallujah, both west of Baghdad, for more than three months, with security forces still struggling to bring parts of the province back under government control.

Early on Saturday, security forces assaulted the Al-Hamira area south of Ramadi, retaking it from militants, an army colonel and a police lieutenant colonel said.

The fighting killed 21 militants and two soldiers, the officers said.

The crisis in the desert province of Anbar erupted in late December when security forces dismantled Iraq's main Sunni Arab anti-government protest camp just outside Ramadi.

Militants subsequently seized parts of Ramadi and all of Fallujah, the first time anti-government forces have exercised such open control in major cities since the peak of the deadly violence that followed the US-led invasion of 2003.

In Mishahada, north of Baghdad, a suicide bomber targeted an army base on Saturday, killing at least four soldiers and wounding six, and bombings in the capital itself killed at least two people.

Militants frequently target members of Iraq's security forces, some of whom lack adequate training and discipline.

Security forces face a major test on April 30 in Iraq's first parliamentary election since American forces left at the end of 2011.

While they were able to keep violence to a minimum during provincial polls last year, the security forces have failed to halt a subsequent year-long surge in unrest.

The heightened unrest has been driven principally by widespread anger among the Sunni Arab minority, who say they are mistreated by the Shiite-led government and security forces.

It has also been fuelled by the bloody civil war in neighbouring Syria, which has bolstered militant groups.

Violence has killed more than 450 people in Iraq this month and upwards of 2,700 this year, according to AFP figures based on security and medical sources.