US President George Bush has pledged that coalition troops in Iraq will not "cut and run" but conceded that the current fighting could be compared to Vietnam.
In an interview with ABC News, the President said levels of violence had increased and that al Qaida was still very active in the country.
When asked if he agreed with a US newspaper columnist who argued that fighting in Iraq was comparable to the 1968 Tet offensive in Vietnam, which undermined then President Lyndon Johnson, the president said: "He could be right".
"There’s certainly a stepped-up level of violence, and we’re heading into an election."
Mr Bush’s remarks were picked up by anti-war groups in the UK who said the situation in Iraq was more grave than Vietnam nearly 40 years ago although militarily it is not yet as costly with the US having lost just over 3,000 troops compared to 51,000 in Vietnam.
Andrew Burgin, from Stop the War Coalition, said: "Iraq is even worse than Vietnam. The US were able to leave Vietnam and the country could find its own path to recovery with a stable government.
"In Iraq they have gone in and kicked the door down, killed 600,000 people and completely destroyed the future of the country."
He went on: "Iraq is much more strategically important than Vietnam from the point of view of the US.
"To lose Iraq, to lose that region is much more important to the US. Vietnam doesn’t have oil and it wasn’t where the US needed to be."
Mr Burgin said he was angry that no senior Labour or Tory politician was prepared to publicly call for the immediate withdrawal of troops.
"That is the shame of the British establishment," he said. "They will have to pull out of Iraq at some point.
"Troops are now dying in large numbers, it is a very desperate situation."
Mr Burgin said coalition troops were not having an impact on the ground and were instead "confined to barracks, rarely going out on patrols".
Mr Bush said he could not see all US troops being withdrawn from Iraq by the end of his presidency in 2008.
"If we were to leave before the job is done, in my judgment, al Qaida would find a safe haven from which to attack," he said.
"My gut tells me that they have all along been trying to inflict enough damage that we’d leave.
"Al Qaida is still very active in Iraq. They are dangerous. They are lethal. They are trying to not only kill American troops, but they’re trying to foment sectarian violence.
"They believe that, if they can create enough chaos, the American people will grow sick and tired of the Iraqi effort and will cause government to withdraw."
But, despite the casualties, the president insisted the US was there to stay.
"The hardest part of the presidency is to meet with families who’ve lost a loved one," he said.
"But I recognise the degree of difficulty of the task, and therefore, say to the American people, we won’t cut and run."
The US president’s comments come a week after the head of the British army sparked controversy by saying troops should pull out "sometime soon".
Sir Richard Dannatt, who became Chief of the General Staff in August, said that we should "get ourselves out sometime soon because our presence exacerbates the security problems".
He also indicated that the Government’s aim of creating a liberal democracy in Iraq was "naive" and would not be achieved. Britain had "effectively kicked the door in" when troops entered during the 2003 military campaign.
"Whatever consent we may have had in the first place, may have turned to tolerance and has largely turned to intolerance."
President Bush awas talking in the wake of reports that a specially-commissioned US task force is drawing up an exit strategy for American forces.
The panel, led by Bush family ally and former US Secretary of State James Baker, is said to think that "staying the course" is an untenable long-term strategy.
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