MOSCOW, JUNE 29 -- The Lithuanian legislature voted today to freeze its declaration of independence in exchange for the start of negotiations with the Kremlin on Lithuania's future and an end to the Soviet economic blockade of the breakaway republic.

The 69 to 35 vote appeared likely to ease a protracted confrontation with Moscow that became an issue of international concern. The legislature agreed to put a 100-day moratorium on its March 11 declaration of independence beginning with the start of negotiations.

The legislatures of the Baltic republics of Latvia and Estonia also have passed independence resolutions, but it was Lithuania's more radical document that most infuriated the Kremlin and set off four months of confrontation. In early shows of force, Soviet tanks rolled through the streets of Vilnius, the Lithuanian capital, and, one night, past the legislature while deputies deliberated inside.

Assuming the Lithuanian compromise plan is accepted in Moscow, an end to the standoff must count as a political victory for Soviet President Mikhail Gorbachev as the Communist Party opens a crucial party congress next week. At a time when conservatives are blaming him for the breakup of the Soviet empire, Gorbachev will be able to point to the blockade and the Lithuanian compromise as proof of his resolve. Yet at the same time, he will be doing what no other Soviet leader has done: negotiating on Baltic independence.

Gorbachev and Lithuanian President Vytautas Landsbergis hammered out general terms for a compromise during meetings this week at the Kremlin and Gorbachev's country residence outside Moscow.

Because the Soviet leadership will be deeply involved in the 28th Communist Party Congress in the next two weeks, negotiations with Lithuania are not likely to begin right away. Landsbergis said, however, that Gorbachev had given his assurance that as soon as the moratorium was approved, Moscow would lift immediately the blockade, which has put tens of thousands of Lithuanians out of work and cut supplies of food, medicine and fuel.

It is still unclear if Moscow will accept Lithuania's proposal to suspend its declaration for 100 days rather than for an unlimited time. Many deputies in the republic's legislature had said they would not have voted for any compromise if the moratorium had been open-ended. But Landsbergis told the lawmakers that they would have the option of extending or putting an end to the moratorium at any time they saw fit and that the compromise would "break the deadlock" with the Kremlin.

{The United States hopes that "this obvious effort by the Lithuanians to bridge their differences with Moscow . . . receives a positive response," State Department spokesman Adam Shub said in Washington. "Of course, the Lithuanian action in no way changes the U.S. position on the non-recognition of the forcible incorporation of the Baltic states into the U.S.S.R." in 1940.

{The United States never recognized the Soviet annexation of Lithuania. However, it disappointed the new Lithuanian government by not recognizing its declaration of independence. President Bush, instead, called for dialogue between Vilnius and Moscow to resolve the issue.}

Until today it was still unclear if the republic's legislature would compromise on its declaration of independence. There is still great distrust of Moscow. Outside the parliament building, a small group of demonstrators held signs pleading with the legislators not to "capitulate to Kremlin blackmail." And during the nine-hour debate, one deputy said, "There is a danger that {Moscow} is deceiving us and trying to bring us to our knees."

Landsbergis's endorsement of the plan on the floor of the legislature today was the breakthrough. Until now, Landsbergis had said such a freeze was "unthinkable." Among other Lithuanian leaders, including Prime Minister Kazimiera Prunskiene, Landsbergis is regarded as the least flexible member of the Lithuanian leadership.

Landsbergis warned the legislators that negotiations with Moscow would not be easy. "The animals will be unchained, there will be threats, there will be pressure. We must be ready for this," he said.

Today's carefully worded Lithuanian compromise resolution said, "The independent Lithuanian state, seeking bilateral negotiations between the republic of Lithuania and the U.S.S.R., declares from the start of negotiations a unilateral 100-day moratorium on the act of March 11, 1990, suspending all legal action arising from this act."

The statement meant that all laws passed by the legislature following the independence declaration would be rendered inactive for the length of the moratorium. Officials in Moscow, including Prime Minister Nikolai Ryzhkov, have said they expect negotiations on the economic, political and social mechanisms of Baltic independence to last two years.