American and Soviet officials, preparing for long-awaited talks that begin this morning between Soviet Foreign Minister Eduard Shevardnadze and senior Reagan administration officials, yesterday predicted in similar terms that Shevardnadze's visit should pave the way for agreement on a new arms control treaty and a U.S.-Soviet summit later this year.

President Reagan announced yesterday that the United States had introduced a draft of the arms control treaty in Geneva, but warned that "difficult issues" need to be resolved before the superpowers can sign the pact, which would eliminate all their land-based medium- and shorter-range nuclear missiles.

Echoing Reagan's caution, Soviet and American officials said yesterday that final agreement on the treaty and a summit is not likely to be completed this week during Shevardnadze's three days of meetings with Secretary of State George P. Shultz, Reagan and others. At the same time, they said that agreement now seems within reach, and that a summit between Reagan and Soviet leader Mikhail Gorbachev could be held as early as late November.

In a statement issued on the eve of his meeting with Shevardnadze, the president said the new U.S. draft of an arms treaty that was presented in Geneva yesterday would contain "the most stringent verification regime of any arms control agreement in history."

"I have always made clear my firm belief that not having a treaty is better than having one which cannot be effectively verified," said Reagan, who has been under fire from conservative supporters for backing away from more stringent verification procedures that the United States had sought until last month, when the administration changed its position.

The president's statement, delivered to the applause of a business group at the Washington Hilton, drew criticism from Soviet Foreign Ministry spokesman Gennadi Gerasimov, who is in Washington. "The U.S. proposal is long overdue," he said. "There was nothing really new in it. They are saying 'yes' to things we proposed."

Gerasimov also said "we are a little bit discouraged that the United States is moving backward on the subject of control," as the Soviets call verification.

Meanwhile, senior U.S. officials confirmed that the United States will not present any new proposals to Shevardnadze today on strategic arms or space weapons being developed under the Strategic Defense Initiative.

Senior Pentagon officials said, however, that in an effort to avoid creating undue conflict with the visiting Soviet delegation, National Security Council staff members persuaded the Pentagon to postpone an announcement that it plans to accelerate research and testing of key SDI technologies in preparation for potential deployment in space of a ballistic missile defense in the mid-1990s. Washington Post staff writer R. Jeffrey Smith reported that the announcement was scheduled for today, but is now likely to come Friday, after the Soviets depart, officials said.

The Soviets remain vehemently opposed to the SDI program. Postponing a Pentagon announcement of accelerated SDI plans avoids a possible diplomatic flap during the Shevardnadze visit.

The key elements of the draft treaty introduced by U.S. negotiators in Geneva yesterday call for eliminating all of the longer-range intermediate missiles -- those with a range of about 600 to 3,000 miles -- within three years, and the shorter-range missiles -- with a range of 300 to 600 miles -- within one year. It would also ban any modernization, production or flight testing of any of these missiles.

Verification procedures included in the draft treaty would allow "challenge inspections" by either side during the period the missiles are being removed and supervision of the destruction process.

Reagan's statement was designed to assuage conservatives, who criticized the administration decision to abandon its earlier demand for more intrusive, continuing inspections after the missiles are dismantled. The president said that "difficult issues remain to be resolved, including verification. The Soviets have said they agree in principle with a number of our verification requirements, but have yet to provide some key details."

When Shevardnadze meets with Reagan today he will bring with him a personal letter from Gorbachev to the president. U.S. officials said they do not know what the letter contained but expressed doubt that it includes a proposal for specific summit dates. A Soviet official gave a similar view.

Shevardnadze and Shultz are scheduled to begin their talks this morning with a three-hour meeting at the State Department, to be followed by a further meeting at the White House with Reagan. At noon they will attend a White House ceremony and sign an agreement, the product of four years of negotiation, to establish "nuclear risk reduction centers" in Washington and Moscow to reduce the risks of accidental war.

Several apparent differences still remain between the United States and the Soviet Union on the proposed treaty to eliminate medium-range missiles, and they emerged yesterday in comments from officials of both countries.

Gerasimov said that "one of our disappointments is that there was no mention of 'warheads' in the president's statement. He mentioned only missiles and launchers. This poses a question mark to us."

A U.S. official said that neither the United States nor the Soviet draft treaties submitted talk about destroying warheads because this would be too difficult to verify. The official suggested that the Soviet effort to talk about destroying warheads, rather than the missiles that would carry them, was an attempt at "propaganda" and unhelpful to the negotiations.

A Soviet official who accompanied Shevardnadze said the Soviet goal is to make the warheads "inoperable" rather than insisting on the destruction of the nuclear material in the warheads, which the U.S. side wants to reuse. He said the Soviet formulation should leave room for the matter to be worked out by experts of the two sides.

The Soviet position, as described by this official source, did suggest one potentially serious hurdle to be overcome in this week's talks. Shevardnadze is seeking "some understanding" here about the West German Pershing IA missiles and U.S. warheads for them which are to be withdrawn from Europe under arrangements announced in Bonn and Washington in recent weeks.

But on this point a senior administration official who briefed reporters at the White House said that "we don't plan to say anything" to Shevardnadze on this subject. "We have said it's not an issue," the U.S. official said.

Although Soviet officials have set forth a variety of conditions that must be met for Gorbachev to come to Washington, this source expressed the belief that a signing ceremony for the treaty on medium-range nuclear missiles would be justification enough for a summit. The official emphasized, however, that the overall atmosphere of U.S.-Soviet relations would be a factor in Gorbachev's decision about coming to Washington and about how long to stay in the country and where to go if he does come.

Meanwhile, 16 senators sent a letter to Shultz asking him to protest the suppression of peaceful demonstrations against Soviet rule that recently took place in the Baltic republics of Latvia, Lithuania and Estonia, annexed by the Soviets in 1939 during the period of their nonaggression pact with Nazi Germany. Administration officials said that human rights issues will be among the topics discussed by Shultz and Shevardnadze.