The media increasingly came under fire in the urban fighting, with two journalists killed and three others injured by US tank fire at a hotel housing foreign reporters and a correspondent for the Arabic TV station Al-Jazeera killed in a separate bombing.

Two US Abrams tanks rolled out of the northern entrance of the presidential palace compound, which US forces raided the day before, and took up position on the adjacent Al-Jumhuriya bridge.

That sparked the first exchange of fire between US forces and Iraqis holed up on the east bank of the Tigris.

Pro-Saddam militiamen clad in T-shirts, jeans and sneakers stationed themselves behind a wall after setting up roadblocks with sandbags, but their Kalashnikov rifles and anti-tank rockets were no match against US firepower, and the tanks pressed on.

Information Minister Mohammed Said al-Sahhaf said the Iraqis had "imprisoned" US forces inside their tanks.

"They are going to surrender or be burned in their tanks," Sahhaf said when asked if it was not time for Baghdad to give up.

He was speaking outside the Palestine Hotel, which houses most foreign journalists still in Baghdad, minutes after it came under US bombardment.

A Ukrainian cameraman for Reuters, Taras Protsyuk, 35, was killed and three other staff members were wounded, the British news agency said in London.

Spanish cameraman Jose Couso died in the same incident after suffering injuries to his leg and jaw, his employer Telecinco said.

General Buford Blount, commander of the US 3rd Infantry Division said a US tank was "receiving fire from the hotel, RPG (rocket-propelled grenade) and small-arms fire, and engaged with one tank round. The firing stopped."

But footage shot by France 3 television showed the barrel of the tank pointed for at least two minutes at the hotel before it opened fire, and without any shots being heard fired in the direction of the tank.

Elsewhere in Baghdad, the correspondent of Qatar-based Al-Jazeera, Tareq Ayub, a 34-year-old Jordanian of Palestinian origin, died after the station's office was hit by a missile.

The network accused the US military of "deliberately targeting" its office, a claim denied by a spokeswoman at US Central Command.

While the United States said it was not targeting journalists, two media organs it has openly wanted to shut down, Iraqi state television and radio, both went off the air Tuesday.

Baghdad's satellite television channel went down on Sunday night and Youth television, run by Saddam's elder son Uday, has failed to broadcast since a missile struck the information ministry at the end of March.

US officials have charged that Iraqi state-controlled media -- known for their incessant victory speeches and denial of any coalition advances -- have been a key factor in preserving Saddam's control.

As hundreds of families left Baghdad for safer places, hospitals braced for more casualties.

"Yesterday was horrible but today will be even worse, judging by the number of wounded brought in this morning," said Kamal Askar, director of the Al-Kindi hospital, where 50 injured were admitted Monday.

In a sign of increasing US confidence in Baghdad, two US Apache attack helicopters flew over the center of the city for the first time Tuesday morning, braving Iraqi anti-aircraft fire.

Warplanes also attacked the massive Republican Palace on the west bank of the river at least twice before fighting inside the compound broke out just before 5:00 a.m. (0100 GMT).

The complex, symbol of Saddam's 24-year iron-fist rule, has been pounded relentlessly since the United States and Britain launched the war March 20 aimed at toppling the Iraqi leader.

For the first time, a US air force A10 "tank killer" plane attacked the Republican Palace, swooping down twice at a very low altitude on the northern entrance of the compound and the nearby planning ministry.

It returned to open fire a third time on an area beyond the planning ministry, apparently on a road leading to the information ministry.

The US military said an A10 later had been hit and gone down near the international airport held by US forces southwest of the city, but that the pilot ejected safely and the aircraft was recovered by coalition ground forces.

There was new speculation on Saddam's fate, as a US official in Washington said a building hit Monday in Baghdad's Al-Mansur district could have been housing the Iraqi leader and his two sons, Uday and Qusay.

"I don't know whether he (Saddam) survived," US President George W. Bush told reporters after a two-day summit in Northern Ireland with British Prime Minister Tony Blair.

A US Central Command spokesman in Qatar said four satellite-guided Joint Direct Attack Munition (JDAM) bombs were dropped.

In Baghdad, witnesses reported that at least 14 civilians were killed when a bomb crashed into Al-Mansur, a residential area. It left a crater eight meters (26 feet) deep and 15 meters (50 feet) wide and destroyed four houses at about 3:00 pm (1100 GMT).

SPACE.WIRE