As many as 120,000 extra US troops are being sent to Iraq as Allied leaders prepare for a siege of Baghdad.
The extra troops, which were being held in reserve, are being sent after the Iraqis put up stiffer than expected resistance and prevented a smaller, fast-moving Allied force from scoring a rapid walk over.
Pentagon officials said there were only 90,000 troops currently in Iraq out of the 200,000-plus troops committed to the war in the original blueprint.
The fact that more troops are being sent in would appear to reflect growing concern about the progress of the war, which US officials say could now last for months.
The Iraqis promised that Baghdad would become a graveyard for the Allies.
Lieutenant General William Wallace, Commander of the US Army V Corps, which is nearing Baghdad, told the Washington Post: “The enemy we are fighting is different from the one we’d wargamed.
“We knew they were there – the paramilitaries – but we didn’t know they would fight like this.”
In Washington, US Defence Secretary Donald Rumsfeld suggested US forces might lay siege to the capital and hope anti-Saddam Hussein citizens rise up against the government, smoothing the way for the Allies.
Mr Rumsfeld also said the coalition would accept nothing short of total victory.
“There isn’t going to be a ceasefire,” Mr Rumsfeld told the Senate Appropriations defence sub-committee.
War commander General Tommy Franks said Iraqi guerrilla attacks on allied supply lines would not slow the advance to Baghdad.
He said the communication lines were “very, very dangerous” but British and US forces had become battle-hardened and adapted to terrorist-style strikes from resistance fighters.
“The force is able to do several things at the same time.
“They’re keeping the supplies moving. What needs to get through is getting through.”
However, the possibility of the war stretching on longer than had been widely expected was acknowledged by Britain's Prime Minister Tony Blair and President George Bush, who vowed to hound Saddam Hussein for “as long as it takes” to drive him from power.
Mr Blair, speaking following two days of talks with President Bush at his Camp David retreat in Maryland, refused to be drawn on suggestions that the war could last months.
The Iraqis predicted that Allied forces would surround Baghdad within five to 10 days but were destined to spend months embroiled in savage street fighting.
As the Iraqi capital was subjected to yet another night of bombardment by coalition forces, Iraq’s defence minister said the allies would have to enter the city eventually.
Sultan Hashim Ahmed told a news conference: “We set up our defences in Baghdad. It will be no surprise that in five to 10 days they will be able to encircle all our positions in Baghdad.
“The enemy must come inside Baghdad, and that will be its grave. We feel that this war must be prolonged so the enemy pays a high price,” he added.
Britain's Prime Minister headed back to Britain today following his talks with Mr Bush and a meeting with United Nations Secretary General Kofi Annan.
Mr Blair emerged from the meeting in New York confident that the UN security council would support a plan to restart the Iraqi oil-for-food programme.
Coalition bombers battered Baghdad again today, hitting a major communications centre and one of Saddam Hussein’s presidential palaces in one of the heaviest bombardments for days.
US officials said a B-2 bomber dropped two 4,700lb satellite-guided “bunker busting” bombs on a major communications tower on the east bank of the Tigris River.
Iraq’s satellite television channel was cutting in and out after the strikes. The US forces had hoped to knock out Iraqi television and radio to disable Saddam’s propaganda outlets.
Further strikes focused on the Republican Guard’s Hammurabi and Medina divisions, which are dug in to the south, west and north of Baghdad, a US military official said.
To the north, cargo planes have been flying supplies to 1,000 US paratroopers who yesterday parachuted in to secure an airfield in Kurdish-controlled northern Iraq.
US forces have been pounding Iraqi positions around Chamchamal over the past few days and recent reports suggest Iraqi soldiers have been abandoning their checkpoints and bunkers and heading west.
In southern Iraq, the first aid shipment to the country was expected to arrive today.
Around 200 tonnes of aid destined for Basra was expected to arrive at the port in Umm Qasr on board the Royal Fleet Auxiliary ship Sir Galahad.
Its arrival has been delayed by unexpectedly fierce Iraqi resistance in surrounding areas which meant the port was not secure and it was prevented from docking after mines were found in the surrounding waters.