20 miles from Baghdad

American armoured forces charged to within 20 miles of the southern edge of Baghdad this afternoon. The rapid advance came after US Brigadier General Vincent Brooks claimed an entire division of the Republican Guard - the Baghdad Division - had been "destroyed".

Success on two fronts earlier today at key cities south of Baghdad was followed by a rapid "rolling attack" on two other Iraqi divisions, the Medina and the Nebuchadnezzar.

Military chiefs in Qatar predicted that allied forces could even seize the chance to reach the outskirts of the capital tonight, depending on the strength of Iraqi opposition.

Forward units of a second advance, from the south-east along the Tigris valley were this afternoon 25 miles from Baghdad and were meeting less resistance than expected.

The 3rd Infantry Division ( Mechanised) pushed beyond the Iraqi's "red line" defensive positions on the approaches to Baghdad - the point at which it was feared Saddam would unleash chemical weapons.

Asked if they would reach Baghdad today, a senior US source said: "Keep watching the television." Ahead of them Apache helicopters blasted missiles at anything in their path, clearing the way for the advance. In the first of a series of dramat ic move s , troops completely encircled the city of Karbala, 68 miles south-west of the capital this morning. They then swept past along both sides of the Euphrates. US units later crossed the Euphrates at a bridge north of Karbala.

In the south-east, US marines fighting the Republican Guard near the city of Kut took and secured a vital bridge over the Tigris. Thousands of US troops crossed the bridge today. Brig Gen Brooks said their advance was "a dagger pointed to the heart" of Baghdad. At Kut the US forces dropped two huge "daisy cutter" bombs, sending giant mushroomshaped clouds billowing into the sky. Troops were this afternoon punching forward on three fronts. The first was north-east from Karbala. Another advanced north-west from Kut where they seized Highway 6 to Baghdad. The third front was moving directly north from the town of Hillah on the eastern side of the Euphrates.

Brig Gen Vincent Brooks said: "Our land component initiated a two corps attack to destroy Republican Guard positions defending Baghdad. First Marine Expeditionary Force attacked the Baghdad Division near the town of Kut. Its leadership is broken, some of its equipment is destroyed. It may mean that we have killed or captured a considerable number of the force to make it possible."

B52 bombers yesterday dropped six precision-guided 1,000lb "cluster" bombs on an Iraqi tank column defending Baghdad to prevent it reinforcing Republican Guards fighting the American advance.

The demise of the Baghdad Division leaves no effective resistance to the Allies' advance from Kut, meaning the 1st Marine Division can now power its way up the Tigris valley.

Brig Gen Brooks said: "The dagger is clearly pointed at the heart of the regime and will remain so until the regime is gone."

Air Marshal Brian Burridge, commander of British forces in the Gulf, said the battle had entered the " decisive phase". A senior Central Command source said: "This could last hours, this could last days. It depends on how the Iraqis respond to us." US troops also seized the Haditha dam on Lake al-Milh, northwest of Baghdad, which could have been used to flood the Euphrates.

Brig Gen Brooks said special forces seized the dam two days ago. There had been "significant regime losses" around the dam, he added. There was growing speculation that Saddam Hussein's regime may be on the brink of capitulation after another night of explosions in Baghdad - observers reported hearing " considerable" small arms fire near the centre of the city last night. Elsewhere, B52 planes hit the northern Iraqi front line near Mosul and US army and airforce attacked Fedayeen militia in Najaf.

In Baghdad, jets screamed low over the city in a series of bombing raids. More than 50 trenches filled with oil were burning in and around Baghdad-At the same time, distant heavy artillery fire could be heard right across the southern edge of the Iraqi capital.

Mohammed Saeed Al Sahhaf, the Iraqi minister of information, said 189 civilians had been killed and a further 24 killed in recent bombing raids in Baghdad.

One US missile hit a Red Crescent maternity hospital and several other civilian buildings, killing several people and wounding at least 25, hospital sources said.

Between 560 and 720 civilians are thought to have been killed since the invasion began 14 days ago.