The foreign secretary has travelled to Iraq for an unannounced visit amid tight security.

Jack Straw touched left Baghdad on Wednesday with a commitment that the coalition forces would remain on the ground in the "long-term".

No pre-warning of the visit was given and the foreign secretary's schedule is remaining secret in the wake of mounting attacks on coalition targets.

He said troops would "stay as long as the Iraqi government and the Iraqi people want us to stay and there is a job for us to do".

"We are here for the long term, and to see Iraq through to a better future," he said.

But he added that the government still expected to see a handover of sovereignty to the people of Iraq by next June.

The foreign secretary also conceded that British and US troops were facing difficulties - but he insisted that real progress was being achieved.

"There has been a great deal of progress in many areas. The security situation remains difficult," he said.

"But I am very clear that the combination of political progress and military effort will ensure that there is a transition on schedule by the end of June, and unquestionably that Iraq not only is a better place, but will become a far better place as a result of that transition and the work of the coalition and our partners internationally, but above all by the work of the Iraqi people."