"As we continue to seize the initiative, we have expanded our area of operations in the city but we haven't added any forces," said Major Mike Birmingham, public affairs officer for the 3rd Infantry Division.

"We just continue to seize the initiative, will continue to push. Hopefully the regime will fall. It's just a matter of time."

Members of the division's Third Brigade were involved in the operation to seize control of the presidential palace while the Second Brigade was conducting operations in downtown Baghdad.

Some 6,000 US troops have set up base around the airport on the southwestern rim of the capital, from where they have been launching raids into the city center.

Birmingham said that the US forces had come under artillery and rocket-propelled grenade fire from members of Saddam's elite Special Republican Guard, but added that "no (US) casualties (were) reported" overnight.

The presence of the US troops in the center of the capital sent a message to the Iraqi people that Saddam's days were numbered, he added.

"They are seeing their leaders are lying to them. The regime is not in control."

US tanks fought their way across the presidential palace compound Tuesday amid heavy exchanges of tank, artillery and gun fire, AFP correspondents witnessed.

After five hours of intense clashes, two US Abrams tanks rolled out of the northern entrance of the compound and took up position on the adjacent Al-Jumhuriya bridge.

Exchanges of fire then broke out with Iraqi forces on the east side of the river for the first time since US armour stormed into the city centre early Monday.

SPACE.WIRE