The United States and its allies in Europe and Japan positioned themselves yesterday to mount an extraordinary economic and possibly a military blockade of Iraq as President Bush dispatched his defense secretary to Saudi Arabia, still threatened by 100,000 Iraqi troops occupying Kuwait.

Meanwhile, Egypt began mobilizing some elements of its armed forces to make them available to assist the Saudi monarchy if it is attacked, according to U.S. and Arab officials. The Egyptian action followed a Bush administration warning that an Iraqi attack on Saudi Arabia would draw a U.S. military response.

Iraq announced that it had begun withdrawing some of its troops that invaded Kuwait on Thursday, and aired videotape on state television of what was described as a "withdrawal operation."

But Bush rejected the claim, charging that Iraq had "lied once again," and that U.S. reconnaissance satellites showed more Iraqi troops moving in to reinforce the invasion force. In Baghdad, state radio reported that Iraqi President Saddam Hussein had ordered his military to form 11 new divisions to supplement his 1 million-man army.

In Kuwait, the new provisional government, installed by Iraq and made up of military officers of uncertain nationality, warned yesterday that foreigners in Kuwait could be endangered by any outside campaign to punish the Iraqi regime.

"Countries that resort to punitive measures against the provisional free Kuwait government and fraternal Iraq . . . should remember that they have interests and nationals in Kuwait," said Walid Saud Muammad Abdullah, who was identified as the foreign minister, on a radio broadcast.

The warning deepened concern in Washington for the safety of American citizens in any military confrontation with Saddam. Bush said there was no "imminent" danger to Americans, as a task force of State Department officials worked around the clock working to locate the 3,800 Americans in Kuwait and 500 in Iraq and help them leave the country as soon as possible.

In New York, ambassadors from the United States, the Soviet Union, Britain, France and China reviewed a draft resolution for the 15-member United Nations Security Council that, if passed, would provide the legal basis for a blockade of the oil output of Iraq and Kuwait. That combined output is roughly one-fourth of the total output of the Organization of Petroleum Exporting Countries.

The draft resolution calls on U.N. member nations to "prevent . . . the export or transshipment of any commodities or products from Iraq or Kuwait."

The United States had been pressing for a vote last night on the resolution, but Arab ambassadors, who were said by U.N. sources to be divided, won a postponement until today or Tuesday.

Kuwait's international airport and sea access remained closed yesterday, and an effort to begin evacuating Americans from Baghdad was delayed. Telephone lines remained inoperable. Kuwait's ambassador to London said 700 Kuwaitis died in the invasion, including seven members of the royal family.

Bush met with his national security advisers into the night and in a brief news conference accused Iraq of lying about its pledge to withdraw from Kuwait. "This will not stand, this aggression against Kuwait," he said.

A diplomatic struggle clearly was underway to win the support of Saudi Arabia and Turkey to join a strong Western stand against the Iraqi president.

Saddam sent a high-level emissary to meet with Turkish President Turgut Ozal yesterday, and Bush said he was trying to reach Ozal for further consultations by telephone. Ozal also conferred with Syrian President Hafez Assad, a bitter enemy of the Iraqi president who accused Saddam of following the law of the "jungle."

International pressure on Iraq grew yesterday, as China joined with Western nations and the Soviet Union in saying it would not sell arms to Iraq. During the eight-year Perisan Gulf war, China was an important supplier of ship-killing Silkworm missiles to Iran and Iraq and provided a version of a Soviet-made heavy bomber to Iraq.

Meanwhile in Japan, Prime Minister Toshiki Kaifu ordered an immediate ban on Japanese oil imports from Iraq and Kuwait and a halt to other commercial activities with Baghdad.

Defense Secretary Richard B. Cheney was dispatched to Saudi Arabia to meet with Saudi King Fahd, and the Saudi ambassador to Washington, Prince Bandar bin Sultan, also flew home. Bandar is the son of the Saudi defense minister, who is recovering from knee surgery in Morocco.

Some Iraqi units continued to maneuver on the Saudi border and minor border incursions occurred for the second day. Saudi Arabia has deployed an armored column of up to 300 tanks near its border, according to an American technician returning to the United States from King Khalid Military City, the desert fortress that guards the northeastern approach to the Saudi heartland.

A formidable armada of U.S., British and French warships was taking up position in the Mediterranean, Arabian and Red seas to enforce a blockade of the Iraqi pipeline terminals if so ordered and to bottle up Iraqi shipping through the Strait of Hormuz, which forms the mouth of the Persian Gulf and is Iraq's only shipping outlet.

U.S. military planning focused on getting carrier and land-based U.S. air forces in place to assist Saudi Arabia if attacked and to strike targets inside Iraq should Iraqi military action escalate and the lives of Americans become threatened.

U.S. special forces teams were assembling at an undisclosed location in the region to be available for assault missions and hostage rescue operations. Officials said there was an unusual amount of military activity around the Masirah Island base off Oman, where U.S. munitions, fuel and other stores are positioned for the U.S. Central Command, which responds to crises in the Middle East.

A U.S. military assessment states that an Iraqi attack on Saudi Arabia could be defeated by combined Saudi and U.S. air forces, according to a military official. The assessment further states that an Iraqi armored thrust toward the Saudi oil fields would collapse after five days if successfully blocked by coordinated Saudi and U.S. air strikes on its follow-on forces, supply lines and front-line units.

Desert temperatures of up to 120 degrees would put a severe strain on a large-scale Iraqi offensive that met substantial resistance, military sources said.

Some officials involved in Arab diplomacy were pressing yesterday for an all-Moslem force of Egyptian, Pakistani and Saudi ground forces to face the Iraqis and make U.S. air support more palatable for the Saudi monarchy, which is extremely sensitive to any open manifestation of its close relations with the U.S. military.

The mobilization of some Egyptian armed forces to aid Saudi Arabia was seen as an effort to keep an Arab stamp on steps taken to respond to the threat from Iraqi forces in Kuwait. Iraq maintains that it has no designs on Saudi Arabia, but administration officials continue to view with alarm the large concentration of Iraqi troops near the Saudi border.

In Egypt, despite a cautious public stance by President Hosni Mubarak, there were signs of military preparations that reflect the growing strains between Mubarak and Saddam. A military official said Egypt had canceled some military leaves and was mobilizing unspecified forces to make available to Saudi Arabia if requested. The official speculated that these would be airborne forces that could be airlifted to Saudi Arabia on short notice.

The focus of the international pressure campaign is likely to shift today to the U.N. Security Council in New York, which will consider the resolution that would effectively require Saudi Arabia and Turkey to stop the "transshipment" of crude oil through Iraqi pipelines that pass through both countries.

Iraq exports about 3.1 million barrels per day, most of it through the pipeline terminals on the Saudi Red Sea coast and Turkey's Mediterranean coast. Kuwait exports all of its oil -- which amounts to 2.1 million barrels produced per day -- by tanker through the Strait of Hormuz.

Former defense secretary James R. Schlesinger dismissed the prospect of blockading such a volume as "impossible."

Yet administration officials appeared to believe that a swift oil cutoff would bring swift results from Saddam, whose nation already is strapped for cash and whose military operations in Kuwait are consuming enormous resources.

The U.N. resolution also would place a total embargo on all Iraqi and Kuwaiti products, and would shut down all international banking lines available to Iraq to conduct foreign trade in oil and other commodities. In addition, it would ban all weapons sales to Iraq.

In Washington, a State Department spokeswoman said that Americans in Kuwait "are being advised to depart as soon as the situation permits and to stay in contact with the U.S. Embassy in Kuwait." In Baghdad, U.S. Embassy officials had contacted 400 of the 500 Americans there and had established contact with Iraqi officials to "ensure the safety" of Americans.