More violence in Iraq

Iraqi insurgents savaged a US patrol overnight, pursuing a violent revolt heedless of Iraqi politicians racing to draft a Constitution that Washington hopes will stabilise the country and reduce its military burden.

US Defense Secretary Donald Rumsfeld said a new Constitution would help undermine support for Sunni Arab rebels. "It's important they stick with their timetable," he told a Pentagon briefing, echoing his earlier call to Iraqi leaders "to get on with it".

A US military statement said the patrol was investigating explosives when a roadside bomb went off, killing four soldiers, and wounding five near Baiji, an oil refining town 180 kilometres north of Baghdad. The soldiers then came under small arms fire. A contractor was also wounded.

A large crater on the highway and an account from Iraqi police suggested US vehicles had been struck by one of what appears to be a new breed of roadside bomb or landmine.

The devices are more powerful than those that have killed hundreds of troops over the past two years and capable of penetrating American armour.

"Clearly, improvised explosive devices... some with newer technologies these days, are going to change our tactics," General Richard Myers told a Pentagon news briefing before the Baiji attack.

Washington's most senior general was responding to a landmine explosion that killed 14 Marines in an armoured amphibious vehicle near Haditha, northwest of Baghdad, on August 3 and to half a dozen other heavy losses in the past two months.

In Baiji, children played around the crater with scraps of US military equipment, including camouflage clothing bearing a soldier's nametag. Local police said they had seen two wrecked Humvee patrol vehicles and a heavy armoured vehicle, all burned.

Guerillas also struck at a checkpoint manned by Iraqi army and police near Baiji yesterday, killing four soldiers and wounding four people, the police said. In other violent incidents, six people, including two policemen, were killed and 14 wounded in Baghdad when a suicide bomber drove a car at a police patrol.

Mr Rumsfeld said bloodshed could rise ahead of a referendum on the Constitution, scheduled for October 15, and a general election due two months later.

Iraq's US-backed government believes advancing a political process which began with elections in January will defuse the in surgency, a loose alliance of foreign Sunni Muslim militants and Saddam Hussein loyalists that shows no signs of weakening.

President Jalal Talabani is hosting a series of meetings this week aimed at breaking deadlock among leaders of Iraq's many communities, including the Shi'ite Muslim majority, ethnic Kurds and Arab Sunnis.

They are under intense US pressure to meet a self-imposed August 15 deadline.