A suicide car bomber has struck the convoy of Iraq's minister of labour and social affairs, killing 11 people and wounding 22 others.

A spokesman for the ministry said the minister, Mahmoud al-Sheikh Radhi, was unhurt.

Three of his bodyguards were among the dead in Thursday's attack.

A Reuters television cameraman in the vicinity filmed the blast, but an Iraqi soldier confiscated his tape.

The cameraman, about 150m away at the time of the explosion, said he saw a car drive into a convoy of six or seven 4WD vehicles and explode near Tahrir square in central Baghdad.

Police and bodyguards in the convoy opened fire after the blast. Several vehicles crashed and others sped away.

Haidar Jamal, an Iraqi journalist, told Al Jazeera: "The explosion took place in Bab Sharji neighbourhood, a few metres away from the Green Zone. Only the Jadiriya bridge links these two areas, and that is why Bab Sharji is mostly frequented by officials heading towards the Green Zone."

Violence across Iraq has fallen over the past year to four-year lows, but fighters are still able to carry out frequent car bomb and suicide bomb attacks.

Suicide bombings are a signature tactic of al-Qaeda in Iraq.