Four bombings within seven minutes have killed six people, including at least three Iraqi soldiers in northern Iraq, while rioting has injured many at Abu Ghraib prison.

Tuesday's early morning attacks appeared coordinated and aimed at checkpoints manned by members of Iraq's fledgling army, which has been a constant target of fighters opposed to the country's new government.

The first explosion, caused by a roadside bomb, rocked Hawija, about 65km south of Kirkuk, at around 9.30am, killing three civilians, Brigadier-General Anwar Mohammed Amin said.

Heavily armed US soldiers sealed off the bomb scene, allowing only ambulances to enter and reach the dead and wounded.

Three car bombers then struck in quick succession, attacking in Bagara, Dibis and at the entrance to Hawija. Amin said three soldiers were killed in the Bagara bombing.

At least 10 people, including soldiers and civilians, were wounded in the various attacks, he added.

Sunni Cleric killed

Also on Tuesday, relatives of a Sunni Muslim cleric in the southern Iraqi city of Basra said he had been killed.

His is the latest in a series of assassinations of religious figures that have stoked sectarian tensions.

Witnesses said Salam Abdul-Karim was taken from his home on Sunday by men in police uniform. His body was found the following day.

Last week, the imam of a Shia mosque was also assassinated in Basra.

Abu Ghraib riots

Meanwhile, several guards and detainees were injured after rioting erupted in the notorious US-run prison of Abu Ghraib on Baghdad's western outskirts after a detainee tried to escape.

"The disturbance occurred shortly after a detainee, using the hours of darkness and a heavy sandstorm, was caught trying to escape," the US military said in a statement on Tuesday.

"Detainees in several of the compounds began throwing rocks at the portable light generators and the guards," it said.

The US military said the incident occurred on Sunday shortly before midnight.

Four guards and six detainees were injured and treated at the scene.

All detainees were accounted for after the disturbance ended, the statement added, without providing further details.

In May, three detainees escaped from Abu Ghraib, the scene of abuse of Iraqi prisoners by their US warders captured in graphic photographs that made headlines around the world in April last year.

PHOTO CAPTION

US troops close off a main road following the detonation of a road side bomb in the northeastern city of Baquba, 60kms from Baghdad, June 6, 2005. (AFP)