The US hit at the heart of Saddam Hussein's regime on Monday, seizing his largest palace complex and briefly surrounding the information ministry from which his version of events has been broadcast around the world.
Iraq's Information Ministry spokesman Mohammed Saeed Sahaf denies that US troops and tanks are in Baghdad.
But the US says more than 70 tanks and 60 Bradley fighting vehicles took part in the lightning thrust into the city's center by the Army's 3rd Infantry Division, with tank-killing A-10 Warthog planes and pilotless drones providing air support against mostly disorganized resistance. F-16s were called in to strike at Iraqi armor on the road ahead.
The bold American daylight raids are far more aggressive - and dangerous - than expected even a few days ago when the cordon of Baghdad began.
In the bombed-out presidential palace, US soldiers used the toilets, rifled through documents, and helped themselves to ashtrays, pillows, gold-painted Arab glassware, and other souvenirs. The Americans also blew up a statue of Mr. Hussein on horseback in the center of the city.
Holding some of these prizes with only special operations forces and battalion-sized forces of a few hundred men may be risky, and the US forces lack sufficient strength to repulse any serious counterattack. But the Iraqi response to American attacks in Baghdad so far suggests the Iraqi military and militias have been seriously degraded.
"The Iraqi air force is not functioning," said US Brig. Gen. Vincent Brooks in Monday's briefing from US Central Command in Qatar. The unchallenged presence of slow, unmanned Predator drones and A-10 Warthog close air support planes flying circles over the city indicates the Iraqi air defense system may be all but obliterated.
Compare the clear skies to the streams of anti-aircraft fire from the first night of the 1991 Gulf War or even the beginning of the current campaign.
The complete American air dominance may make it difficult for the Iraqis to mass forces of any significant size in one place anywhere in the city. Low-flying F-16s and other jets armed with ground attack missiles are flying shotgun with convoys, blasting any tanks lying in the way.
These relatively small convoys of about 100 US tanks and armored personnel carriers have been able to penetrate into the center of the city with impunity. They have suffered some casualties - including a command center for the 3rd Infantry Division brigade leading the assault - from small arms fire and rocket propelled grenades. But the relatively light and sporadic resistance suggests Iraqi ground forces may be all but incapable of launching a coordinated counter attack.
It remains unclear where the tens of thousands of Hussein's Special Republican Guards, militiamen and intelligence officers may be hiding within the city. Unlike the first two probes by US ground forces that left thousands of Iraqi combatants dead, the Monday raids seemed narrowly targeted on reaching those key buildings. Still, even if Hussein's most loyal and tenacious fighters have melted into the city's civilian population, they may now be trapped inside the city.
The First Marine Division and the Army's 101st Airborne and Third Infantry Divisions have now completed the cordon of the city, making it nearly impossible for Iraqi forces inside to get fresh supplies or reinforcements.
An American C-130 landed at the newly-named Baghdad International Airport late Sunday, the first known US aircraft to land since the fall of the airfield. A seven-hour firefight into early Monday between US and Iraqi troops at the airport resulted in the deaths of some 100 Iraqis wearing military uniforms.
In southern Iraq, the British say that the top Iraqi official known as "Chemical Ali" was killed in a strike on his home. Ali Hassan Al Majid, one of the most brutal members of Hussein's inner circle, was killed by an airstrike on his house in Basra, a British officer said Monday. He had been dubbed "Chemical Ali" by opponents for ordering a 1988 poison gas attack that killed thousands of Kurds.
A massive convoy of British infantry has rolled into Basra from the southern outskirts in what appears to be a major move to secure the old section of the city, meeting little resistance.