MOSCOW, NOV. 7 -- Secretary of State James A. Baker III said today that "the credibility of the United Nations is at stake" because of Iraqi President Saddam Hussein's refusal to leave Kuwait and Senior officials said it was becoming clear that a new U.N. Security Council resolution authorizing use of force will be necessary to maintain international consensus if the Persian Gulf crisis comes to war.

As Baker continued his quest for international support, the White House prepared to spell out its plans to augment its ground forces in the gulf, giving them new firepower for offensive operations. Administration officials said President Bush would announce within a day or two his decision to deploy at least two additional tank divisions, with the first troops coming from Europe.

Baker flew here tonight for talks with Soviet President Mikhail Gorbachev and Foreign Minister Eduard Shevardnadze on whether the Soviet Union will support such a resolution authorizing the use of force to liberate Kuwait. Earlier today, Baker discussed diplomatic and military aspects of the campaign against Saddam with President Turgut Ozal of Turkey, who faces both political and economic strains from the gulf crisis.

Ozal advised Baker that more time is needed for the sanctions to work and change Saddam's behavior. A senior State Department official traveling with Baker said, "The question is, are the sanctions yet having an effect that would alter Saddam's political calculus and lead him to withdraw peacefully and otherwise fully implement the resolutions? We're obviously not yet to that point."

U.S. officials said military options were discussed with Ozal but they would not give details. Turkey has stationed about 100,000 troops along its border with Iraq. This has been met by a parallel Iraqi troop buildup. While there has been some speculation that this is part of a two-front strategy against Saddam, Ozal last weekend said a conflict with Iraq on its northern front was a "figment of the imagination."

The United States has been pressing Saddam with blunt talk of the "possible use of force" to drive him out of Kuwait. But as Baker and others sharpen the talk, they are coming to grips with the political problem of sustaining a broad international consensus for armed conflict.

The senior State Department official said that "at every stop" on Baker's tour, leaders have stressed the importance of maintaining the international solidarity. Saddam has tried to fragment the coalition by selectively releasing hostages to other nations and seeking to forestall any military strike.

After seeing Ozal, Baker emphasized that both Turkey and the United States see "that the credibility of the United Nations is at stake. . . . It's very important that when the United Nations takes actions -- passes resolutions and takes action -- that those resolutions and actions be implemented."

At the United Nations, diplomats said the United States is sounding out member countries on a resolution that would authorize the use of U.N. military force against Iraq, the Associated Press reported. But the diplomats said the text has not yet been circulated to other Security Council members because Baker is still trying to line up support for it.

British Prime Minister Margaret Thatcher, meanwhile, delivered a tough warning to Saddam today in her address to the opening session of Parliament, Reuter reported.

"Either he gets out of Kuwait soon," she said, "or we and our allies will remove him by force. He will go down to defeat with all its consequences. He has been warned. Time is running out for Saddam Hussein." {Thatcher's comment helped drive up the price of oil $2.68 to $35.31 a barrel in futures trading in New York, according to traders quoted by AP. Details on Page B16.}

Baker and other officials have said the United States believes it currently enjoys sufficient authority to launch a military strike under Article 51 of the U.N. Charter, which allows for collective security. But officials stressed today that while that may be a good legal argument, the political reality is that it would be hard to sustain international support by going it alone if Washington decided military action had become necessary.

A senior official aboard Baker's plane recounted how the use of force was tested in the debate over naval interdiction last August. At first, the United States appeared ready to go it alone and stop shipping to and from Iraq. But after protests from members of the Security Council, the United States decided to seek a resolution endorsing naval interception, thus making it easier for the other nations to go along.

The official told reporters that "legally" the basis for action to liberate Kuwait is contained in the U.N. Charter and requests for help from the exiled government of Kuwait and from Saudi Arabia. But, the official said, "it is our belief" that a specific Security Council resolution authorizing force "would provide a firmer political base" for military action. And, the official added, "I think the idea is to try to maintain that international consensus as you move further along in this crisis."

Administration officials have not yet disclosed the details of such a resolution, in part because Baker is hoping this week's talks with the four other permanent members of the Security Council will produce language that all five members with veto power -- Britain, France, the United States, China and the Soviet Union -- could support. It is not clear, for example, whether the resolution would provide a blanket authority for action, or specific conditions and circumstances in which it would be allowed.

In his meetings today with Ozal and Turkey's prime minister and foreign minister, Baker got a taste of why many countries in the anti-Iraq coalition are insisting on the cover of a U.N. resolution.

Ozal has been under increasingly strident political attacks at home for his stand against Saddam. Political assassinations have increased in Turkey, two cabinet members have resigned and opposition leaders have accused Ozal of exceeding his constitutional authority. The opposition is urging that Turkey stay out of military conflict altogether.

The senior U.S. official also told reporters that the United States has expressed a willingness to "do what we could" to help a U.N.-sponsored mission to resupply the besieged American and British embassies in Kuwait. Assistant Secretary of State John Bolton met last week with U.N. Secretary General Javier Perez de Cuellar to plan the mission, officials said, but they gave no details.

Ozal appealed to Baker to open American markets to Turkish textiles as a means of relieving the strains on Turkey's economy from the economic sanctions against Iraq. According to the World Bank, Turkey has suffered major hardships as a result of the sanctions, including about $7 billion annually in lost revenue from the closed oil pipeline from Iraq, lost trade and construction business, lost debt payments from Iraq and a drop in tourism.

While Baker continued his travels, John Kelly, assistant secretary of state for Middle East affairs, met in Damascus today with Syrian officials. The officials told reporters that the talks were related to a planned meeting there Tuesday of the foreign ministers of Syria, Saudi Arabia and Egypt, Reuter reported.

Kelly said that the aim of his visit was to consult with Syrian officials "on the current situation in the gulf" and to give them a report on Baker's talks. He said the issue of Syrian complaints about increased U.S. military and economic aid to Israel had come up "and we both stated our views clearly."

State Department officials said tonight that American arms control negotiators had flown to Moscow for a new round of discussions on the treaty on conventional forces in Europe and on the unfinished strategic arms treaty.

Although originally Baker was planning to devote most of his meetings here to the Persian Gulf crisis, the presence of the negotiators could indicate fresh efforts to resolve stumbling blocks in the strategic arms pact, and a final effort to work out last-minute hitches in the conventional forces treaty, scheduled to be signed Nov. 19 in Paris.

The White House said today that Bush, who will be in Paris for the signing of the treaty, will probably meet with Gorbachev there, in the fourth meeting of the two leaders.

Meanwhile, Yevgeny Primakov, Gorbachev's special envoy for the gulf crisis, told reporters here tonight that he had seen in talks last month with Saddam last month indications that Saddam's position was changing. Primakov met Saddam Oct. 5 and Oct. 28 in Baghdad.

"Between our first talks and our second, there was a big difference," he said. "At the first meeting, he insisted Kuwait was part of Iraq. At the second, there was no mention of this."

"When I put it quite definitely to him, 'If you don't withdraw there will be a military strike against you,' he showed he was in a position to do something. . . . I was more optimistic and I remain optimistic," said Primakov, a specialist on the Middle East.

Primakov said remarks by Gorbachev in Paris recently that had raised some concern the Soviet president was not solidly behind the alliance had been misinterpreted.

The Soviet Union, Primakov said, "is not stepping down from the common platform" with the other members of the international coalition.