The tanks were seen rolling into the heart of Baghdad on the western side of the Tigris River, which divides the city. The US forces were taking up positions in the city's center.

Explosions and gunfires were heard, black smoke was arising and US warplanes were flying over the city, live pictures of Qatar-based al-Jazeera satellite television show.

It's said two US tanks entered the presidential palace.

Major Michael Birmingham, chief public affairs officer for the US 3rd Infantry, was quoted as saying: "We're attacking right down in the center of the city right now."

"The other day was just an incursion. This is for real," he added, referring to a foray US armored forces made into southwest Baghdad on Saturday.

On Sunday, a US C-130 military transport plane landed at Saddam International Airport for the first time since the war started, the US Central Command said.

"We can confirm that a C-130 landed at Baghdad airport," said Lt. commander Herb Josey, a spokesman for the US Central Command in Qatar.

The military transporter landed at about 8 p.m. local time (1600 GMT), he added.

US forces said on Friday that they have seized the airport, some 20 km southwest of the Iraqi capital center, despite sporadic fire from remnants of the Iraqi Republican Guard forces.

At least 5000 US troops have been deployed at the airport, including units of the 101st Airborne Division, US military said.

But Iraqi officials vehemently denied the US claim, saying that Iraqi troops have killed more than 500 US soldiers in fighting in the area.

Another 50 US soldiers were killed and 16 US tanks destroyed close to Baghdad airport overnight, Iraqi Information Minister Mohammed Saeed al-Sahaf told a press briefing on Sunday.

He noted that Iraqi forces fired rockets at US troops in the vicinity of Saddam International Airport overnight while the Republican Guard forces are tightening the noose around the enemy forces around the airport.

US Forces Say Attacking Central Baghdad

The US military said that its ground forces were attacking central Baghdad early Monday morning, shelling presidential palace in the east of the capital.

Witnesses said explosions were heard when two bombs hit the center of Baghdad early on Monday and more struck the outskirts of the Iraqi capital. Heavy artillery fire could be heard from the south.

Major Michael Birmingham, chief public affairs officer for the US 3rd Infantry, was quoted as saying: "We're attacking right down in the center of the city right now."

"The other day was just an incursion. This is for real," he added, referring to a foray US armored forces made into southwest Baghdad on Saturday.

(Xinhua News Agency April 7, 2003)