AMERICAN troops were on the streets of Baghdad this morning as the war went to the heart of the Iraqi regime.Tanks were seen on the streets of the capital, and troops were reported to be searching one of the main presidential compounds in the city.

ALLIED troops launched an attack on central Baghdad this morning, seizing key buildings in the city.

Members of the 3rd Infantry Division took over a presidential palace and the Iraqi information ministry, it was reported.

The city was rocked by explosions as tanks rolled into the heart of the Iraqi capital.

General Peter Pace, vice chairman of the US Joint Chiefs of Staff, said troops had entered the city with the aim of "destroying the enemy".

He said they were conducting "armoured raids''.

Forces had driven though parts of Baghdad, seizing "significant numbers'' of tanks and armoured personnel carriers and "destroying all of the enemy vehicles and personnel with whom they've come in contact.''

"One of the points is to destroy the enemy that we found, and the last two raids have been very, very successful at doing that,'' Gen Pace said.

Sky News reporter David Chater said he could hear a lot of explosions to the west of the city and could see flames and large plumes of smoke rising.

Earlier, US military commanders claimed to have Baghdad encircled, with all the main routes in and out under their control.

And after two weeks, the Desert Rats and Royal Marines stormed into Iraq's second city Basra yesterday and now have large swathes under their control, though the price was the death of three British soldiers.

US forces had now formed a loose circle around Baghdad, seeking to isolate it and block movement of Iraqi troops in and out, American officers said.

Gen Pace said the city was surrounded although he stressed that did not mean there was "an impenetrable cordon around the city''.

"We do control the highways in and out of the city and do have the capability to interdict, to stop, to attack any Iraqi military forces that might try either to escape or to engage our forces.''

And a further boost to coalition forces came when a US military cargo plane landed at Baghdad's international airport last night, the first known US aircraft to arrive in the Iraqi capital.

However, the US Marines attempts to hold a main bridge leading into the southern outskirts of Baghdad were foiled by Iraqis who disabled it with explosives, meaning the bridge would not be able to hold tanks and heavy vehicles. Another bridge four miles away was also disabled.

BBC correspondent in Baghdad Rageh Omaar said: "From my hotel balcony I can see two American tanks right in the heart of Baghdad. They are near one of the presidential compounds.

"There's a fire burning and black smoke and explosions everywhere.

"I've seen mortar rounds firing as well and there's the sound of heavy machine gun fire from the area of the presidential compound.''