A US commander said around 1,000 Iraqi troops had been killed in the drive into the battered city, and an AFP reporter saw dozens of Iraqi military vehicles burning in the streets.

"It was hell," said Kamal, an electrician from the Yarmuk district in southwest Baghdad about 10 kilometres (six miles) from the city centre.

"The firepower was incredible. There was no let-up in the firing for three hours. Machine gun fire, light artillery and RPGs (Rocket-Propelled Grenades)," he said. "We were on a battlefield."

Iraq had warned troops around Baghdad and the international airport, 20 kilometres (12 miles) southwest of the centre of the city, would be hit Friday night with "non-conventional" and "martyr" attacks.

A US military spokesman said troops had "moved" into Baghdad, after rolling in from the airport. AFP reporters said they saw no US forces in the city at mid-day, several hours after the first push inside city limits around 0100 GMT.

"This wasn't a patrol -- go in and come out," spokesman and Navy Captain Frank Thorp said at US Central Command's planning base in Qatar.

He later told CNN: "We have coalition armoured combat formations right in the heart of Baghdad," adding: "This is a desperate regime. They're on their last legs." He said the coalition was holding more than 6,000 Iraqi POWs.

Colonel David Perkins, commander of the Second Brigade of the US Army's Third Infantry Division, which sent dozens of tanks into the Iraqi capital, said the casualty toll among the Iraqis was "estimated at about 1,000 KIAs (killed in action)."

Iraqi bodies were "all over the streets," he said Saturday, as US troops in and around Baghdad were engaged in the fiercest fighting sincethe war to topple Saddam Hussein was launched on March 20.

Perkins said the US forces destroyed about 100 pieces of Iraqi equipment, including air defence systems, tanks, rocket-propelled grenade launchers, recoilless rifles and guided anti-tank missiles.

Another spokesman at Central Command said 30 tanks had gone into the city and that "patrols and operations" were being conducted.

Colonel Will Grimsley, commander of the First Brigade of the US army's 3rd Infantry Division, described it as: "Let me poke you in the eye because we can and you can't do anything about it."

Grimsley said tanks had "looped through the city center" as a show of force, adding that elements of the Second Brigade had come under fire from rifles and RPGs as they moved toward the city centre.

Thorp said there had been no hand-to-hand or house-to-house combat but said that in Baghdad and elsewhere, tough battles were ongoing.

"I think you would describe the fighting as fierce," he told Sky News.

AFP reporters heard artillery fire booming on the edge of the Yarmuk and Doha neighbourhoods along the road leading to Baghdad airport, seized by US troops on Friday, and huge fireballs were seen over the airport.

Iraqi Information Minister Mohammad Said al-Sahhaf insisted that Saddam's elite Republican Guard was in "full control" of the airport.

"We have defeated them, in fact we have crushed them," he told a press conference in the capital. "The whole trend has been changed. The operation is moving in our interests and I think we are going to finalise soon."

Lieutenant Colonel Scott Rutter, commander of the 27th Infantry Battalion of the 1st Brigade, said clashes with Iraqi forces continued around the airport late Friday.

"Between 100-120 enemy" fighters were killed by his battalion in clashes on Friday afternoon and evening after they launched a counter-offensive, he said.

Loud explosions were still rattling the capital Saturday morning after another night of almost continuous heavy bombardment. AFP reporters said they were coming from the southwestern edge of the city near the airport.

Rutter said six Iraqi T-72 tanks, five Iraqi armoured personnel carriers and "teams" of Iraqis firing rocket-propelled grenades had been destroyed.

There was no overall word on American casualties but US officers said a US tank commander was shot and killed, and two other soldiers wounded, in Baghdad.

Two pilots were also killed Saturday when their AH-1W "Super Cobra" attack helicopter crashed in central Iraq. Three US soldiers were killed in a vehicle accident Friday at the airport.

Outside Baghdad, Thorp said, US marines pushing up from the southeast were clashing with the Al-Nida division of Iraq's elite Republican Guard. "They moved into their midst and are engaging them," he said.

Military sources said earlier that the marines had taken the city of Al-Kut, 150 kilometers (95 miles) to the southeast.

Elsewhere, Major Mike Slocum told AFP that Black Hawk, Chinook and Apache helicopters were transporting more than a battalion of soldiers into the outskirts of the southern holy city of Karbala.

Central Command said Friday that US and coalition forces had control of the roads in and out of Iraq as well as the route between Baghdad and Tikrit, Saddam's hometown to the northeast and a key seat of his tribal support.

In northern Iraq, US special forces and Iraqi Kurd rebels have cut off the southern exits from the northern oil centre of Kirkuk, and are operating within five kilometers (3 miles) of the strategic northern city, Kurdish military sources said Saturday.

The officials from the Patriotic Union of Kurdistan (PUK) said two main highways leading south of Kirkuk were unusable by Iraqi forces, and that most of the Iraqi army units had pulled back within city limits.

Sky News and Britain's domestic Press Association reported that hundreds of human remains were discovered by British soldiers in a makeshift morgue in southern Iraq on the outskirts of Al Zubayr, near Basra.

The remains, including bundles of bone in strips of military uniform, were found in an abandoned military base. It was not known how long they had been there.

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