The Pentagon is now facing the prospect of the US-led war against Iraq lasting months rather than weeks as originally planned, with an assault on Baghdad postponed for many days to allow time for reinforcements to arrive. Conor O'Clery, North America Editor, reports from New York.
This was the grim military assessment confronting President Bush and the British Prime Minister, Mr Blair, at their meeting in Camp David outside Washington yesterday. Both leaders pledged Iraqi president Saddam Hussein would be ousted, however long it took.
In Washington, Defence Secretary Donald Rumsfeld predicted "some of the toughest fighting" lay ahead as US combat troops encircling Baghdad encountered the Republican Guard, but suggested that instead of a frontal attack the city might be besieged in the hope of a popular uprising against Saddam.
The most ominous US assessment of progress in the week-old war came from a senior American general in the field, where the US-led advance has been slowed by bad weather and unexpectedly ferocious guerrilla attacks on long and insecure supply lines stretching over 300 miles.
"We didn't know that they would fight like this, the enemy is different to the one we 'war-gamed'," said Lieut Gen William Walker, commander of the US 5th Corps. Asked by an American reporter with his troops if the war would take longer than planned he replied, "It's beginning to look that way."
At a press conference after their overnight summit in Camp David, where they discussed the Middle East peace process and the reconstruction of post-war Iraq, neither Mr Bush nor Mr Blair would speculate how long the war might take.
"This isn't a matter of timetable, it's a matter of victory, and the Iraqi people have got to know that, see," said Mr Bush. "And the Iraqi people have got to know that, see."
Jabbing his finger on the lectern to emphasise every word, he said: "They got to know that they will be liberated and Saddam Hussein will be removed, no matter how long it takes."
The US-led forces were "engaging the dictator's most hardened and most desperate units", Mr Bush said. "The campaign ahead will require further courage and further sacrifice."
Mr Blair had come to the summit with two goals, to get Mr Bush to recommit to the "road map" for progress to a Palestinian state by 2005 and to persuade Mr Bush that any post-conflict administration be endorsed by the UN, officials said.
Mr Bush agreed the US would "soon" release the road map and that both countries were "strongly committed to implementing" it. However, he did not commit the US to handing over to the UN. Mr Blair had argued that a new administration would have no legal cover without a new UN resolution.
The reconstruction of Iraq seemed a distant problem as the two leaders reviewed a war that is proving bloodier and more protracted than predicted.
Reports have appeared in the US media, citing senior US officers in the field, that much of the Army's lethal fleet of 100 Apache attack helicopters have been grounded by weather and battle damage.
The Washington Post reported it could take a month for the US Army's 4th division with tanks to get into position and provide reinforcing cover for combat troops. Other US forces heading to the region will require months to move their tanks and heavy armour.
In Washington, Secretary of State Colin Powell said it was becoming evident that the war "may take a little longer", contradicting the Pentagon spokesman Maj General Stanley McCrystal, who claimed the campaign was "right on the mark".
The setbacks for the US-led forces are seen in Washington as a vindication of the case made during war planning by overall commander of US forces in the region, Gen Tommy Franks, for a greater number of troops on the ground before any invasion.
The Pentagon announced last night that an additional 120,000 ground troops are to join the 90,000 in Iraq.
Mr Rumsfeld, who favoured a smaller force relying on high-tech equipment and "shock and awe tactics", blamed "death squads" numbering 5,000 to 20,000 people among the pro-Saddam Hussein Fedayeen irregular forces for forcing Iraqis to fight.
At a Senate hearing yesterday Mr Rumsfeld was asked about diplomatic efforts by Arab nations for a ceasefire. "I have no idea what some country might propose, but there isn't going to be a ceasefire," he replied.