Six policemen were killed in the blast in Ramadi [AFP]

At least 17 people, including a number of police officers, have been killed in a suspected suicide car bomb attack on a government building in Iraq, according to officials.

The explosion took place in the centre of the city of Ramadi in the western Anbar province on Sunday.

"It [the explosion] was at a crowded crossroad. There were civilian vehicles passing and it is also the entrance to the main government offices," Hikmet Khalaf, the deputy governor of Anbar, told the Reuters news agency.

"The death toll could rise because there are people who are critically wounded."

Major Rahim Zabin, a police official, told the AFP news agency: "A suicide car bomb targeted a police checkpoint in the centre of the city, about 200 metres from the Anbar government offices."

A doctor at Ramadi hospital, who spoke on condition of anonymity, said medics had so far treated 35 people for injuries, including women and children.

Second bomb

A second bomb was reportedly found in a nearby car park but was detonated safely.

In another attack in Baquba, northwest of Baghdad, a man wearing an explosive belt attacked a procession of Shia Muslims, killing at least two people and injuring three, according to security sources.

"This really does break the lull of the past couple of weeks when its been fairly quiet," Al Jazeera's Jane Arraf, reporting from Baghdad, said.

"Ramadi was the location of a series of very high-profile arrests announced by the government recently. They say they have rounded up some of the top al-Qaeda leadership there.

"This attack may be a message ... saying they are still there."

Less than a year ago, the Islamic state of Iraq, an al-Qaeda affiliate, claimed responsibility for an attack on the same compound.

Ramadi lies about 100 kilometres west of Baghdad and is the capital of the predominantly-Sunni Anbar province, Iraq's biggest by area.