US troops were drawn into a new offensive in the northern Iraqi city of Mosul yesterday to tackle a tide of insurgency unchecked by the military assault on Falluja.
In Baghdad at least 17 Iraqis were killed in a suicide car bombing as gunmen set up checkpoints on roads in the west of the capital and fought battles with US troops.
The violence suggests the four-day operation in Falluja may have cleared out the most important insurgent stronghold in Iraq, but has done little to curb the burgeoning militant movement.
For two days insurgents have defied a curfew to run rampage through Mosul, attacking or setting fire to at least seven police stations as well as government buildings.
Masked gunmen stole bullet-proof jackets and Kalashnikov rifles from police stations and were roaming the city centre yesterday setting fire to police cars and taking control of bridges. The five bridges over the Tigris were later closed to civilian traffic.
At one stage a group tried to storm an office of the Patriotic Union of Kurdistan, one of the two major Kurdish parties, and fought gunbattles with Kurdish guards. Mosul's TV channel went off air for an hour and the US military admitted the Iraqi police were unable to handle the crisis. At least five Iraqi national guardsmen and a civilian have been killed and a dozen injured.
By 1 pm a brigade of soldiers from the US 25th Infantry Division and a team of Iraqi national guardsmen were called in to launch "offensive operations" in south-east and south-west Mosul against "known concentrations of insurgents".
A senior Kurdish official in Mosul said he believed the gunmen were militants loyal to the wanted Jordanian Abu Musab al-Zarqawi and former Ba'athists. He said the men had arrived three days ago from Falluja and Samarra, another troubled Sunni town.
The official, who declined to be named, said: "They are working together and know what they are doing."
Since the start of the Falluja offensive on Sunday night, attacks have taken place across Sunni areas in central and northern Iraq. The violence in Mosul has been the worst since the invasion began and a sign of the growing influence of Sunni militants.