News of the maneuver came as US forces consolidated their hold on the main airport southwest of the city and began around-the-clock air patrols to support ground troops in an expected major push on the capital.

Major Rod Legowski said the Third Brigade of the US Army's 3rd Infantry Division circled Baghdad northwards from the west while the Marines pushed towards the city from east of the Tigris river.

Legowski, the First Marine Division's liaison to the 3rd Infantry Division, said the objective was to establish a cordon around Baghdad in the 18-day-old US-led drive to oust Saddam.

"The whole city will be cordoned by the end of the day," the major said. "We think by the end of today, it (Baghdad) will be totally surrounded."

He made his remarks a day after US forces followed up a dramatic seizure of Baghdad's airport by sending dozens of tanks into the capital in a show of force and a bid to probe Saddam's remaining defenses.

Fierce clashes were reported Saturday and a US commander said about 1,000 Iraqis had been killed. In a new wrinkle Sunday, Legowski said that nationals from other Arab countries were also involved in the fighting.

"Egyptians, Jordanians and Syrians are in the fight alongside Iraqis," Legowski said. He gave no further details and did not say whether they were regular soldiers or volunteers.

The US-British coalition kept up the pressure on Baghdad from the air, with warplanes swooping over the capital and sporadic blasts shaking the southern outskirts on Sunday following overnight missile strikes.

AFP correspondents said that around the same time, bombing was clearly heard in the city centre from the southern rim where artillery blasts had resumed by mid-morning.

US commanders said that US fighter aircraft were stacked up over Baghdad, poised to use precision bombs to protect US ground troops as they move through the streets of the Iraqi capital.

Lieutenant General T. Michael Moseley said that once ground troops entered the city, a plan went into effect to position forward air controllers continuously in aircraft above and on the ground to spot potential targets.

Moseley, who commands the US air war, said avoiding civilian casualties while providing close air support to troops in the city was "a tough problem" that US forces hoped to overcome with precision strikes.

"The trick is -- if you have to do this -- is to use the smallest munition possible to get the maximum effect so that you don't create those unnecessary losses of civilian life or property," he said in a telephone conference call with reporters from his headquarters in Saudi Arabia.

Cleaning up operations continued at the airport 20 kilometers (12 miles) outside Baghdad. US commanders said they controlled 95 percent of the facility, with some 5,000 troops in place.

Meanwhile, the US 101st Airborne Division launched an air assault to secure the Shiite Muslim holy city of Karbala, some 90 kilometers (55 miles) southwest of Baghdad.

Major Mike Slocum told AFP that helicopters had transported more than a battalion of troops into the city's outskirts.

In northern Iraq, Kurdish fighters and US special forces, supported by targeted air strikes, advanced towards the cities of Mosul and Kirkuk after engaging Iraqi forces in the first battles in the region.

Less than 10 days after first crossing the demarcation line that separates Kurdish-held territory from the rest of Iraq, Kurdish peshmerga fighters have made advances on six separate roads to Mosul and the oil-rich city of Kirkuk following heavy bombing of Iraqi positions by coalition forces, AFP correspondents said.

They were seen moving with or ahead of US special forces, who have been calling in targeted air strikes as evidenced by bomb craters at Iraqi positions.

In the southern port of Basra besieged by British troops, British tanks were reported Sunday to have entered the city centre, according to Britain's domestic news agency the Press Association.

It quoted an unnammed military source at the headquarters of the US Central Command in Qatar as saying there was some "stiff fighting" in Basra early Sunday.

Also in Basra, a bodyguard of the notorious Saddam Hussein cousin and aide known as "Chemical Ali" was confirmed dead in a coalition air strike, but there was no word on the fate of Ali himself, US officials said.

They said the corpse had been identified in the wreckage of Saturday's strike on the house of Ali Hassan al-Majid, who won his grisly nickname for ordering gas attacks that killed thousands of Kurds in 1988.

SPACE.WIRE