More than 300 British marine commandos entered Iraq's northern city of Zakho Wednesday and began protecting Kurdish refugees from Iraqi police. The White House said the police were hindering relief efforts.

Two British officers said the United States had given the Iraqis 24 hours, or until Friday morning, to leave the town, but a U.S. military spokesman denied an ultimatum had been given.The allied show of force came as President Saddam Hussein held talks with Kurdish rebel leaders. Rebel sources said Saddam offered new terms for granting autonomy to Iraq's 3.5 million Kurds.

Three companies of British commandos landed by helicopter and took up key positions in the northern, southern and eastern parts of Zakho, near where U.S. troops are setting up a secure haven for tens of thousands of Kurdish refugees.

The commandos reported encountering no resistance from the Iraqis, who were still patrolling Zakho Wednesday despite U.S. demands that they stay clear of the relief effort.

The British soldiers will patrol the town along with other allied troops. Fear of the Iraqis has made some refugees reluctant to move out of their mountain refuges along the Turkish border.

"The Iraqis were given 48 hours to get out," said Capt. Jeff Mason, whose 100-member company took over a three-story building that belonged to the Iraqi army. He said the U.S. military had given the ultimatum within the past 24 hours - meaning the Iraqis had to be out by Friday morning.

"A deadline was imposed and if by that time they haven't withdrawn we can assume military action will continue," said British Maj. Bob Fanshawe, a spokesman for the Royal Marines.

He said the ultimatum was given during daily meetings between the U.S. military liaison, Col. Dick Naab, and Iraqi Staff Brig. Gen. Nushwan Danoun.

However, a U.S. military spokesman denied an ultimatum had been given. "There has been no deadline set for the police to get out of town," said Army Col. Bob Flocke.

At Incirlik, the U.S.-Turkish base that is coordinating relief efforts, U.S. Maj. Michael Maher said: "We have nothing on such an ultimatum."

In Washington, White House spokesman Marlin Fitzwater Wednesday said Iraqi forces patrolling northern Iraq are inhibiting Kurdish refugees from leaving their mountain sanctuaries. However, he said U.S. forces were "working around" the problem. He said he would check reports about the ultimatum.

Asked about the Iraqi police, he said: "They're there. Their purpose appears to be to establish a presence. It's a matter of concern, of course."

Allied troops have pitched hundreds of tents outside the northern town of Zakho in an attempt to lure some of the hundreds of thousands of refugees off rocky mountainsides on the nearby Turkish border.

The United States said Tuesday it is moving ships to positions off Turkey to make it clear that Baghdad had better not interfere with the refugee assistance effort.

In other developments:

- United Nations peacekeepers Wednesday raised their blue flag in place of the American Stars and Stripes on a rusty pole in the sweltering desert town of Safwan, Iraq.

But a U.S. colonel said his troops won't leave Iraq until safety is guaranteed for refugees, many of whom fear reprisals for their roles in the failed uprising against Saddam.

"We will continue to protect the refugees," Col. Bill Nash told the head of the U.N. observation post, Lt. Col. Peter Feely, an Irishman.

- Some of the Iraqi warplanes flown to Iran during the war to escape destruction are being painted with Iranian air force insignia, diplomats said, indicating Tehran plans to hold on to them.

Iraq claims nearly 150 of its planes were flown to Iran during the war, but Tehran says it plans to return fewer than two dozen.

- Japan's Prime Minister Toshiki Kaifu's Cabinet on Wednesday approved sending four minesweepers to the Persian Gulf in Japan's first overseas military mission since World War II.

The decision comes two months after the end of the gulf war and culminates nine months of heated debate over the use of Self-Defense Forces, Japan's military, abroad.