"It is not over," the spokesman told a Downing Street press briefing on day 22 of the US-led war, adding that the fate of president Saddam Hussein remains unknown.

"There are still dangers we should not underestimate," he said.

Defence Secretary Geoff Hoon, speaking on Sky News television, struck a similar note, saying: "We have to guard against being over-optimistic."

At the Foreign Office, an official said Wednesday's scenes of jubilation in Baghdad "demonstrated that Saddam and his regime are steadily losing their grip on power, and the Iraqi people realise that this really will be the end of Saddam's regime."

But he added: "There's a large military job to be done, and part of that is to stablise Iraq before Iraqis can enjoy their new-found freedom."

"We urge all pro-Saddam Hussein forces to recognise that the days of the regime are numbered and there's little point in resistance," the official said.

On the key northern Iraqi city of Kirkuk, the official said the Foreign Office was checking reports that it had fallen Thursday to US-backed Kurdish forces.

SPACE.WIRE