The army convoy was heading over Jamhuriya bridge spanning the Tigris river on Monday when explosives were detonated. One of the Humvees they were travelling in was overturned, while the other was damaged.

In another incident, an unconfirmed number of US soldiers were hurt in Baghdad’s al-Tayran tunnel. Smoke was seen billowing from the underpass though military officials prevented reporters from accessing the scene.

North of Baghdad, US troops carried out pre-dawn raids on Monday, ramming down gates, kicking in doors and arresting Iraqis suspected of having links to militia fighters thought to be behind attacks on occupation forces.

“This sends a message to the bad guys: 'We will hunt you down',” said Lieutenant Colonel Steve Russell, who led the simultaneous raids that targeted Iraqis hiding throughout
Tikrit.

Pipeline blasts

Unidentified assailants also exploded a pipeline in Northern Iraq, linking two oilfields, a local civil defence official reported.

The explosion damaged the pipeline connecting the Janbur and Kirkuk oilfields. There was no initial information as to the extent of the damage.

It is unclear as to whether the attack will delay exports from Kirkuk to the Turkish terminal of Ceyhan on the Mediterranean. The US is relying on these exports to help pay for the war-damaged country’s reconstruction.

Commander Saleh Muhammad, a civil defence representative, said the explosion occurred aout 15km south of Kirkuk, according to AFP.

The US-led Coalition Provisional Authority said in a telephone interview that it could not confirm the blast.