The allies have demanded that Iraqi security forces leave this northern town where a tent city is being built for Kurdish refugees, and the police appear to be heeding the call.

The Iraqi police presence in Zakho has frightened Kurds who fled to the mountains on the Turkish border and are now being urged to return to Iraq.In Washington Thursday, White House spokesman Marlin Fitzwater said the United States, Britain and France have warned Baghdad to withdraw its security forces from the Zakho area by this weekend.

The joint statement was delivered Wednesday to Iraqi officials at the United Nations, Fitzwater said. He said the statement did not set a specific deadline but, he added, "We would expect them to be out by this weekend."

In a show of force meant to assure the refugees, about 300 British Royal Marines landed by helicopter on Wednesday and drove through the town. They pledged to protect inhabitants who were complaining of intimidation by the black-bereted Iraqi police.

Some police appeared to be driving away Wednesday, and one Iraqi officer told The Associated Press: "Tomorrow we leave."

About two-thirds of Iraq's Kurds fled to the Turkish and Iranian frontiers after their failed uprising and many have expressed a reluctance to return unless the Western allies assure them lasting protection.

But the long-term need for the camps, which U.S., British, French and Dutch troops have pledged to defend, has been called into question by Wednesday's agreement in Baghdad between Saddam and Kurdish rebel leaders.

In southern Iraq Thursday, U.N. peacekeeping troops spent their first full day manning checkpoints they took over from U.S. soldiers, but the Americans remained.

"We're not moving out, we're just handing over this spot," Col. Bill Nash of the 3rd Armored Division said as a dozen soldiers turned over a checkpoint to U.N. observers.

The post marked the first formal presence by the United Nations in a demilitarized zone that stretches six miles into Iraq and three miles inside Kuwait.

The United Nations established two other posts Wednesday, one west of Safwan and the other in the Iraqi coastal town of Umm Qasr. The peacekeepers' Austrian commander, Maj. Gen. Gunther Greindl, said, "The Iraqi authorities have cooperated very well."

Greindl predicted it would take about two weeks for the full 1,440-member contingent from more than 30 countries to be deployed.

Nash, of Hayden, Ariz., said roughly 5,000 troops under his command would remain in southern Iraq to provide security and humanitarian aid to thousands of Iraqi refugees.