GENEVA, JAN. 11 -- On the eve of his planned meeting with Iraqi President Saddam Hussein that may be the last opportunity to avert war in the Persian Gulf, U.N. Secretary General Javier Perez de Cuellar heard assurances today from European foreign ministers that they would push for an international conference on the Middle East soon after a complete Iraqi withdrawal from Kuwait.

Perez de Cuellar, whom a diplomat here described as "the world's last messenger for peace," said he is willing to ask the U.N. Security Council to approve a neutral peace-keeping force that could be deployed to preserve peace along Iraq's borders with Kuwait and Saudi Arabia. But he stressed that this could only happen once Iraq agrees to withdraw its forces behind its own borders, a process that would be monitored by U.N. observers.

Four days before a U.N. Security Council deadline for Iraq to withdraw from Kuwait or face war, the 12 foreign ministers from European Community countries held a 75-minute meeting with Perez de Cuellar at U.N. headquarters here about his planned talks with Saddam Saturday. They said the U.N. chief would spell out a multi-stage process endorsed by their governments that is designed to assure Iraq of peace and security if it carries out a total and unconditional withdrawal from Kuwait. However, Perez de Cuellar denied here and upon his arrival tonight in Amman, Jordan, that he was taking "concrete proposals" to Baghdad.

German Foreign Minister Hans-Dietrich Genscher said the Europeans agreed their plan was "a good idea" that they fully supported. A peace-keeping force, he said, "could be Arab."

Several ministers said the secretary general intended to open his meeting with Saddam by delivering a blunt, double-barreled message: If he withdraws from Kuwait, he will not be attacked; if he does not, he will be expelled by force.

If Saddam agrees to withdraw, the ministers said Perez de Cuellar was prepared to offer sufficient guarantees that Iraq would not come under military attack and cite the strong European backing for an international Middle East conference. Arab and Western statesmen who have met with Saddam since he invaded Kuwait more than five months ago say those two issues are central to persuading Saddam to retreat.

Both President Bush and Secretary of State James A. Baker III have stated that the United States would not attack Iraq if Saddam withdraws from Kuwait, and the U.S. president, in a television interview last month, said that "the United States would be very pleased to support" a U.N. peace-keeping force.

The United States long has favored the idea of a properly structured international conference on Middle East issues that would include consideration of ways to resolve the Palestinian issue. It has supported resolutions in the Security Council taking that position.

But both Bush and Baker have specified repeatedly in recent weeks that such a conference should not be linked to Iraqi withdrawal from Kuwait, and have publicly opposed efforts to establish such linkage on the grounds that it would be an unacceptable reward for Iraqi aggression.

Israel vehemently opposes an international peace conference to resolve the Palestinian issue, and the government of Prime Minister Yitzhak Shamir has vowed not to cooperate in any way with such a conference. Israeli opposition to an international conference is based partly on calls for the participation of the Palestine Liberation Organization, which Israel claims is a terrorist organization and refuses to deal with.

Israel also insists that the Arab conflict must be resolved in direct negotiations with its Arab adversaries. Israeli officials are said to distrust what they see as the Europeans' desire to gain influence in the Arab world, and feel the nations of Europe would gang up and try to sacrifice Israel's interests, and press the United States to go along.

Today, White House spokesman Marlin Fitzwater, asked about any post-withdrawal assurances for Saddam, including the idea of a U.N. peace-keeping force, said, "We aren't willing to discuss arrangements after the withdrawal because we don't want anything to appear as a condition.

"We demand the unconditional withdrawal from Kuwait, period. And after it's over, after that happens, then we'll talk about where we go from there."

Soviet President Mikhail Gorbachev telephoned President Bush in Washington today with new ideas for a possible diplomatic initiative to avert war in the four days before the U.N. deadline, setting off a round of meetings between the two countries to explore the ideas in more detail.

Bush and Gorbachev spent 25 minutes on the phone this morning, and Bush reported that the Soviet leader was "thinking innovatively" about how to get Saddam to withdraw from Kuwait.

Bush met later in the morning with Soviet Ambassador Alexander Bessmertnykh at Gorbachev's request, and then held a second meeting with the Soviet envoy during the afternoon.

There were no immediate details available about Gorbachev's proposal. Bush would say only that Gorbachev "had some ideas he wanted to discuss with me" and called the conversation "very important."

Asked if Gorbachev had requested more time for economic sanctions before the possible initiation of military action against Iraq, Bush said: "I'm not going to go into any details, but that would be incompatible with full implementation of the resolution. So I guess I could say no to that one."

A senior administration official said Gorbachev's ideas were not related to the meeting in Baghdad between Saddam and Perez de Cuellar, but were "within the parameters" of the U.N. resolutions.

The U.N. chief's mission was undertaken after the collapse of talks between the United States and Iraq here Wednesday. Although sharply disappointed by the standoff in the talks, European leaders have remained undaunted in their efforts to pursue a breakthrough until the last moment before the U.N. deadline. "It may well be that the meeting {Wednesday} has an impact, although not immediately," Genscher said.

Yet the absence of any sign that Iraq is contemplating a withdrawal and the continuous stream of bellicose rhetoric from Saddam in recent days do not augur well for Perez de Cuellar's pilgrimage to Baghdad.

"I hope I will be heard, and I hope I will find a wish for peace," he said upon his arrival in Geneva today. "I don't dare say I am optimistic but even so I hold out hope."

"He is the world's last messenger for peace," said Jacques Poos of Luxembourg, which holds the EC's rotating presidency. But if Perez de Cuellar's efforts should fail, Poos said, the EC was ready to step in with more last-minute appeals and possibly seek direct contacts with Saddam. "Nothing is excluded," he said.

However, Poos said European governments agreed to invest their hopes for the moment on Perez de Cuellar's trip and refrain from any further diplomatic initiatives on the gulf conflict until they learn the outcome of his discussions with Saddam.

Portuguese Foreign Minister Joao De Deus Pinheiro said the European Community's "post-crisis" peace plan consisted of five stages, beginning with Iraq's announced intention to fulfill U.N. resolutions and pull out of Kuwait. The successive features include: no Western attack, guarantees that foreign forces will be withdrawn, U.N. observers to monitor the Iraqi retreat and a neutral peace-keeping force installed along the borders, and an international Middle East peace conference to deal with all security problems in the area.

"If the Iraqis do not accept this package, then we will know that they want war," said Pinheiro.

Perez de Cuellar is also expected to offer assurances that the multinational force based in Saudi Arabia would be pulled out once Iraqi troops are behind their own borders. Once the military confrontation subsides, an international peace conference on the Middle East would take over the final resolution of security questions.

The U.N. chief will carry a promise from the European Community that it will do all it can to convene an international conference dealing with the Arab-Israeli conflict and the Palestinian question as soon as possible after the Iraqi withdrawal.

The European ministers insisted that they were not making a direct linkage between Iraq's occupation of Kuwait and the Arab-Israeli conflict. "There is no linkage involved, but there are problems to be faced" in the post-crisis era that also need urgent resolution, such as the Israeli-Palestinian conflict, said Luxembourg's Poos.

By making the offer of an international conference and other security guarantees entirely contingent on Iraq completing a withdrawal from Kuwait, European officials said the EC peace plan did not involve a quid pro quo that could be seen as a reward for the Iraqis.

"None of these things will happen unless, and only unless, the Iraqis have left Kuwait," a French source said. "We all agree that nothing can happen before they pull out, and therefore we see no conflict with the U.N. resolutions."

Staff writers Dan Balz and John M. Goshko in Washington contributed to this report.