BAGHDAD: More than 30 people were killed in fresh violence in Iraq yesterday.

At least 20 people died when a bomber blew himself up at a funeral north of Baghdad.

The attack occurred in Sadiyah town in Diyala province, where US and Iraqi forces are battling Al Qaeda in Iraq militants.

Police said the bomber mingled among the mourners and then triggered an explosive vest.

In other violence, the US military said it killed at least six suspected militants and captured 20 in raids across northern Iraq.

A roadside bomb killed three policemen and wounded two others when it struck their patrol in Mussayab, 60km south of Baghdad. A US helicopter fired on militants at the request of Iraqi forces in Basra. Several houses were damaged.

Moqtada Al Sadr yesterday called for one million Iraqis to march against the US occupation of Iraq. The demonstration will be held in Baghdad on Wednesday marking the fifth anniversary of the fall of Baghdad.

Meanwhile, a top UN official warned of "very grave" humanitarian problems in Iraq, including a lack of food and the internal displacement of more than two million people.

"There are very grave humanitarian problems, the most serious is the internal displacement of the Iraqis... this is a phenomenon which we believe has slowed down significantly in recent months," UN under-secretary general for humanitarian affairs John Holmes said.

An estimated 700 people were killed and more than 1,500 wounded in the clashes between government forces and Shi'ite militants, the UN's Humanitarian Co-ordinator for Iraq David Shearer said.