US FORCES launched a large ground and air offensive against insurgents in Mosul yesterday in an effort to retake areas lost to the rebels in heavy fighting last week.

As US Marines wrapped up their operations in the city of Fallujah, American commanders faced the daunting task of stamping out violent uprisings in a string of cities and towns across central Iraq. Although the Americans have hailed the recapture of Fallujah as a big victory against the insurgency, many rebels have escaped and are intent on causing havoc across central Iraq.

Last week, aware that American forces were concentrated in Fallujah, they launched an audacious attack against government buildings in western Mosul, seizing nine police stations and controlling parts of the city.

The offensive yesterday by 1,200 American soldiers from two US Army battalions, backed by 300 Iraqi National Guardsmen, was an attempt to restore order. Witnesses said that the Americans sealed off the five main bridges over the River Tigris, which divides the city, and then launched an operation to clear rebels street by street. As they moved, helicopter gunships and fighter-bombers struck repeatedly at suspected insurgent positions.

“We are in the process of securing all of the police stations and returning the police to these stations to put in place a strong police presence,” a US army spokesman in Mosul said. “Some of those stations are in neighbourhoods on the western side of the city, where there has been insurgent activity and presence. We are now moving through the neighbourhoods.”

It was not clear whether the rebels had stayed to fight or had melted away. Before the assault, three police stations had been blown to pieces by the insurgents, who then withdrew. They also attacked convoys travelling near Mosul and fired mortar rounds at the government headquarters in the city centre.

There were also reports of fighting around the main US base located in a former palace belonging to Saddam Hussein.

Controlling Mosul is vital for the United States-backed Iraqi Government if it hopes to restore a semblance of order over the country in time for elections, which are due to take place in two months’ time.

However, the operation may be just the start of a rolling campaign to stamp out rebel attacks that have spread throughout the so-called Sunni Triangle, the area of central Iraq where the insurgency is most active.

Yesterday, Abu Musab alZarqawi, the Jordanian militant commander responsible for suicide car bombings and the kidnappings and killings of foreigners, urged rebels to rise up against US forces across the country. In an audiotape posted on an Islamist website, he called on fighters to prevent American troops from attacking other cities after Fallujah.

“The enemy is weak and cannot widen their battle, so do not stop at expelling them . . . advance towards them and rain rockets and mortars down on them,” he said. “Make sure that the reins of the battle are in your hands and not in theirs.”

His instructions were followed in several areas of Iraq. Saboteurs blew up oil and gas pipelines near Kirkuk, where firefighters were still trying to put out the blaze from weekend attacks.

Accodingly, fires on the two pipelines that were targeted, one carrying oil and the other carrying gas, could not be tackled, said Lieutenent Colonel Marwan Omar of the Iraqi Government force responsible for securing such installations.

“The firefighters are busy with the oil well fire,” he said. “The attack against the oil pipeline was very powerful, but the blast on the gas pipeline was smaller. Both were sabotage.”

In Baqubah, northeast of Baghdad, heavy fighting broke out yesterday afternoon between American troops and insurgents, who used small arms and rocket-propelled grenades.

In Latifiyah, south of Baghdad, local people discovered the bodies of 18 people wearing Iraqi National Guard uniforms and laid out in the desert. Some had been decapitated.

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