"The fighting lasted from five to eight o'clock this morning (0100 GMT to ," said Kamal, an electrician from the Yarmuk district on the road to the airport.

"It was hell. We were on a battlefield. It was on the airport road about 10 kilometres from the airport.

"The firepower was incredible. There was no let-up in the firing for three hours. Machinegun fire, light artillery and RPGs (Rocket-Propelled Grenades)."

A US commander had earlier said a contingent of troops backed by tanks rolled into the city of Baghdad on Saturday from the airport area they hold and came under fire.

"It started at first light," said Colonel Will Grimsley, commander of the First Brigade of the US army's 3rd Infantry Division.

Grimsley said elements of the division's Second Brigade had come under rifle fire and attack by RPGs as they entered the city. He did not give the size of the US force advancing.

He was speaking at Baghdad airport a day after US forces seized control of most of the facility in their 16-day-old drive northward to topple Saddam's regime.

CNN reported that US armour had penetrated the "heart of Baghdad" encountering occasionally stiff resistance from Iraqi forces using RPGs and horizontally fired anti-aircraft weapons.

SPACE.WIRE