A suicide car bombing followed by an assault by grenade-throwing gunmen on a police headquarters in a disputed city in north Iraq killed 30 people. The vehicle that was detonated in central Kirkuk was painted to appear as though it was a police car, and the militants who sought to seize the compound were dressed as policemen, witnesses said. (Photo: Ako Rasheed / Reuters)

The attack shattered a relative calm in recent days in Iraq, which has been grappling with a political crisis pitting Prime Minister Nuri al-Maliki against his erstwhile government partners amid weeks of ongoing protests calling for him to resign, less than three months before key provincial elections. Photo: Marwan Ibrahim: AFP)

A suicide car bomber killed at least 21 people in an attack on a busy market in a town north of Baghdad on Tuesday, a security official said.

Dozens more were wounded when the attacker blew up the vehicle in the middle of the fruit and vegetable market in Tuz Khurmatu, the official said.

There was no immediate claim of responsibility.

Suicide attacks in Iraq are usually claimed by the Islamic State jihadist group, which has suffered a string of military defeats and last week lost control of the last town the jihadists held in the country.

Tuz Khurmatu is home to a mixed Kurdish, Arab and Turkmen population. It was the scene of deadly violence in mid-October when Iraqi forces retook it from Kurdish control in response to a Kurdish independence referendum.