Now some of these tasks will be ceded to Iraqi troops for good.

Under proposals laid out by Prime Minister Tony Blair on Wednesday, Britain will withdraw about 1,600 troops from Iraq over the coming months and hopes to make other cuts to its 7,100-strong contingent by late summer.

British troops would likely stay in the southern Basra region until at least 2008, training local forces, working to secure the Iran-Iraq border and maintaining supply routes to U.S. and coalition troops in central Iraq, Blair told legislators.

Britain could further reduce its force level to below 5,000 once a base at Basra Palace is transferred to Iraqi control in late summer, the prime minister said.

"What all of this means is not that Basra is how we want it to be. But it does mean that the next chapter in Basra's history can be written by Iraqis," Blair said.

The announcement, on the same day Denmark said it would withdraw its 460 troops, comes as the U.S. is implementing an increase of 21,000 more troops for Iraq ¡ª putting Washington on an opposite track as its main coalition allies.

Secretary of State Condoleezza Rice played down the British pullback, saying it is consistent with the U.S. plan to turn over more control to Iraqi forces.

"The British have done what is really the plan for the country as a whole, which is to transfer security responsibility to the Iraqis as the situation permits," Rice said. "The coalition remains intact and, in fact, the British still have thousands of troops deployed in Iraq."

The Islamic State of Iraq, an al-Qaida linked insurgent group, called the British decision "the beginning of the disintegration of the crusader coalition," according to a posting on a militant Web site translated by Washington-based SITE Institute, which monitors terrorism Internet messages.

The group, which has claimed responsibility for several recent downings of U.S. helicopters, also called on insurgents to block roads used by the coalition forces, saying time was "crucial."

British troops have performed many humanitarian tasks ¡ª helping open hundreds of schools, fitting hospitals with modern equipment and replacing leaky water pipes ¡ª but some say the real British legacy is likely to be a consolidation of Shiite control.

British forces already acquiesced to a "situation of quiet sectarian cleansing" in the south, said Anthony Cordesman, an expert on Iraq at the Washington-based Center for Strategic and International Studies. The decision to pull out of Basra only underscored the political reality of Shiite primacy in the region, he said.

Rear Adm. Richard Cobbold, director of the military think tank Royal United Services Institute in London, said Britain's decision to pull back "needed to be made."

"I would admit that there is a sense of uncertainty, but things are not getting better with the British in Basra," he said. "The British are aggravating tensions by just being there."

British troops have mounted recent operations against Shiite militia, most notably raiding a Basra police station in December that had been run by a rogue police squad and freeing 70 people held captive.

Some analysts fear a militia resurgence once British troops withdraw and warn Iran may attempt to step up its influence in the region.

Blair's official spokesman, on customary condition of anonymity in line with policy, acknowledged British officials "still believed Iranian supplied ordinance is coming across the border."

But Blair said the decision to withdraw was made because the south had "no Sunni insurgency, no al-Qaida base, little Sunni on Shia violence." The Iraqi capital Baghdad, however, was suffering from what he called an "orgy of terrorism unleashed upon it in order to crush any possibility of it functioning."

The other major coalition partners in Iraq include South Korea (2,300 troops), Poland (900), Australia and Georgia (both 800) and Romania (600), according to the Brookings Institution.

South Korea plans to halve its 2,300-member contingent in the northern city of Irbil by April, and is under pressure from parliament to devise a plan for a complete withdrawal by year's end. Polish President Lech Kaczynski has said his country's troops would stay no longer than December.