LONDON (Reuters) – It is critical for Iraq to reach an agreement in the next few weeks permitting British troops to stay in the country after a U.N. mandate expires at the end of this year, a British Foreign Office minister said Tuesday.

Iraq and the United States have been negotiating for months over a security agreement to settle the status of American troops once the mandate enacted after the 2003 invasion expires.

Once those negotiations are complete, Britain, which has 4,100 troops in Iraq, wants to secure a similar agreement.

“What is critical is that actually in the next few days and weeks we resolve this issue because were we to reach the end of the year and we had to roll over the United Nations’ mandate, I think that would send out an unfortunate message that would undermine the genuine progress that is being made,” Foreign Office minister Bill Rammell told the BBC.

He was speaking from Baghdad where he said he was discussing the so-called “status of forces agreement.”

Reaching agreement was important to show that British troops were no longer in Iraq under United Nations authority but under an explicit agreement with Iraq’s government, he said.

Iraq and the United States say the U.S. force, which now numbers about 146,000, is still needed to protect Iraq despite dramatic improvements in security over the past 18 months.

Among the contentious issues are deadlines for the U.S. troops’ withdrawal and the question of whether they can be tried for crimes in Iraqi courts.

Iraqi Prime Minister Nuri al-Maliki was quoted by The Times Monday as saying British combat forces were no longer needed to maintain security in southern Iraq.

“We’ve always said that we wanted to reduce our troop levels as and when the Iraqis were able to secure the situation for themselves…I think you will see further reductions,” Rammell said.