President Bush and Soviet President Mikhail Gorbachev have postponed next month's Moscow summit meeting until sometime before the end of June, the two governments announced yesterday after talks that dealt extensively with Soviet internal developments as well as with the Persian Gulf War.

Secretary of State James A. Baker III and Foreign Minister Alexander Bessmertnykh, making the announcement following a White House meeting with Bush, blamed the postponement on the status of the war and difficulties in completing the landmark strategic arms reduction treaty (START). Members of Congress as well as Baltic Americans had asked Bush not to go to Moscow on Feb. 11, as originally scheduled, while a military crackdown continues in the Baltic states.

White House officials, who described the session as "workmanlike," said a significant portion of the meeting with Bush dealt with the Soviet use of force in the breakaway republics of Lithuania, Latvia and Estonia. The president "basically restated his position" and suggested to Bessmertnykh that "he needed to understand the difficulty this {U.S.} relationship will have if the situation does not improve over the next weeks," a senior U.S. official said.

The Soviet foreign minister, for his part, said Moscow opposes the use of force in the Baltic states, according to the U.S. official, and declared that "the situation is improving and will improve."

U.S. sources said Bessmertnykh, the former ambassador to the United States who succeeded Eduard Shevardnadze as foreign minister two weeks ago, went out of his way to assure Bush and Baker of the great importance that Gorbachev continues to place on the U.S.-Soviet relationship. They said he reiterated Moscow's continued solidarity with the U.S.-led allied effort in the gulf.

An official involved in the talks said Bessmertnykh expressed "a serious desire to work with us" despite the sharp reaction in the West to the military crackdown in the Baltics and what is seen in the West as a swing to the right by Gorbachev on other issues.

One reflection of congressional concern about Soviet actions in the Baltics came yesterday when the Senate Foreign Relations Committee postponed action on a pending U.S.-Soviet maritime boundary treaty. Committee Chairman Claiborne Pell (D-R.I.) said approval of the treaty "under current circumstances" would "send the wrong signal" to Moscow.

In Vilnius, Lithuanian President Vytautas Landsbergis said he hoped the postponement would not encourage more Soviet military aggression in the Baltics. "It is not so important what reason {for the postponement} is named," he said. "It is more important what reasons are in mind."

Bush's wish to postpone the planned summit was stated by Baker in his initial meeting with the Soviet minister Saturday afternoon and Bessmertnykh readily agreed, according to U.S. sources. It was the Soviet side that first suggested a commitment to reschedule the meeting sometime in the first half of this year rather than leave an indefinite postponement, the sources said.

Speaking to reporters at the State Department prior to his meeting with Bush, Bessmertnykh said Moscow has "removed the troops that have been introduced there {to the Baltic states} lately. So what is left there is only the troops that were there before."

State Department officials said, however, they had no information from the Baltic area indicating that recently arrived Soviet troops have been withdrawn.

Most of Bessmertnykh's talk with Bush was taken up with discussion of the Baltic situation, according to the U.S. sources. "We have made our substantial concerns known to the Soviet Union in a substantial way," Baker said following the White House meeting.

White House press secretary Marlin Fitzwater said the Baltics as well as other issues were addressed by Bush in a letter to Gorbachev that was delivered in the Soviet capital last Thursday.

Gorbachev and Bessmertnykh raised eyebrows in official Washington with recent remarks warning against "escalation" of the military conflict in the gulf and suggesting that U.S. and allied air attacks in Iraq might exceed the limits of U.N. Security Council resolutions authorizing the use of force to expel Iraq from Kuwait. Since beginning his talks here Saturday, however, Bessmertnykh has emphasized that Moscow is not seeking to disassociate itself from the U.N. resolutions or the allied effort, according to U.S. participants in the talks.

In his public remarks after the White House talks, Bessmertnykh said that "the Soviet Union and the United States are acting together in accordance with" the U.N. resolutions, and spoke of the "mutual goal" of Washington and Moscow in getting "the aggressor back from the country he occupied." He said he had only been trying to warn of "a danger" of escalation "which may not be predicted or controlled" flowing out of the logic of military actions.

A U.S. concern was that the Soviet Union might be preparing to throw its weight behind an appeal for a cease-fire in place, especially if such a proposal were to be made by Iraqi President Saddam Hussein. But an official who participated in the talks said Bessmertnykh stated clearly that the Soviets "don't support the effort for a cease-fire" unless it is "made absolutely clear in an iron-clad fashion" that Iraq is leaving Kuwait.

In announcing the postponement of the summit, the two ministers said that "work on the START treaty will require some additional time" for completion. Bush and Gorbachev had hoped to sign the treaty during the Moscow meeting.

Baker, who is to meet with Bessmertnykh again today to discuss arms control issues, said the two sides agreed in the White House talks that they will continue to work to complete the START treaty during February, despite postponement of the summit meeting.

The State Department announced that the chief U.S. negotiator in START, Richard Burt, has resigned to join a private consulting firm. Several officials said Burt's resignation, which will take effect in several weeks, was due to his frustration over the slow pace of the negotiations. But Burt insisted in a telephone interview that this was not the case and that he hoped the accord could be completed before his departure.

Staff writer R. Jeffrey Smith contributed to this report.