VILNIUS, U.S.S.R., JAN. 13 -- Soviet military officials here declared a strict curfew in Lithuania today as the people of this Baltic republic mourned 13 persons killed in an attack early this morning by Soviet paratroops. Lithuanians said they feared the troops would soon attempt to seize the parliament building.

By about 10 p.m. this evening, most of the thousands of people who had gathered around the parliament building had dispersed as the military and the Lithuanian government apparently reached a temporary truce to avoid further bloodshed.

Meanwhile, leaders of neighboring Latvia and Estonia said they have received reports that Soviet paratroops were preparing to enter their republics, which like Lithuania declared independence from Moscow last year. Officials there expressed fear that Moscow would crack down soon, perhaps as early as Monday, and U.S. officials in Washington said such a move seems particularly likely in Latvia.

Soviet President Mikhail Gorbachev maintained public silence on the violence in Vilnius, the Lithuanian capital, in which Soviet troops backed by tanks and armored vehicles seized the republic's radio and television complex. Thirteen people were killed, including two who were run over by army tanks, and at least 140 wounded.

Many here blamed Gorbachev for the army assault, but Boris Yeltsin, president of the Soviet Union's Russian republic, said in Estonia tonight that Gorbachev had told him in a telephone conversation that he did not order the attack, according to the Baltic news agency Baltfax.

Yeltsin told reporters in Tallinn, the Estonian capital, that he had spoken as well with Defense Minister Dmitri Yazov, who also denied ordering the assault but who said that one of the army leaders in Lithuania might have.

Meanhile, the status of Lithuania's government and parliament, which 11 months ago became the republic's first popularly elected legislature in a half-century, was in question. Immediately after the assault on the broadcast center this morning, a group aligned with the Lithuanian Communist Party and calling itself the National Salvation Committee declared that it had taken control of the republic.

Soviet Interior Minister Boris Pugo went on national television tonight and accused Lithuanian independence demonstrators of provoking the violence in Vilnius. Speaking on the news program "Vremya," Pugo charged that the demonstrators fired first on the army troops, a version of events that was contradicted by witness accounts of numerous reporters on the scene, including this correspondent.

The violent crackdown was denounced widely by democracy movement leaders at demonstrations around the Soviet Union and by Western governments.

In Tallinn, Yeltsin and representatives of the three Baltic republics signed two joint declarations. One was a letter to the United Nations asking that the international body hold an immediate conference on the Baltic crisis and asking the U.N. Security Council to postpone its Jan. 15 deadline for an Iraqi withdrawal from Kuwait to "relieve pressure on the Baltic situation." The other condemned the military action in Lithuania and pledged mutual assistance in the event of further violence.

Just 40 minutes before the eight-hour curfew was due to take effect in Vilnius tonight, Lithuanian President Vytautas Landsbergis announced that the military had agreed not to fire on people overnight if they began returning to their homes. "You have defended our right to our independence and shown that you are afraid of nothing," Landsbergis told legislators in a speech that was broadcast to crowds outside.

However, about 2,000 Lithuanians remained outside the building at midnight, insisting that they would remain to the end. "We have no moral right to leave. If we left, the people who are inside the building would be alone. If there is an attack, we have to be here," said Marija Jasuvaitis, who had traveled to Vilnius by bus from nearby Kaunas.

Most of the bloodshed here took place at around 2 a.m., when troops stormed the television center and tower on Cosmonaut Avenue and began firing live ammunition at crowds gathered there. At one point, a line of about 50 people stood in front of an approaching tank column; two people, a 17-year-old man and a 24-year-old woman, were crushed under its treads. The tanks fired deafening blank charges and swung their gun turrets as soldiers fired live rounds from AK-47 assault rifles.

In Lithuania and across the Soviet Union, people said the scenes were reminiscent of Moscow's invasions of Hungary in 1956 and Czechoslovakia in 1968.

"What is at stake here is not Lithuania. Lithuania is just the pretext," said Algirdas Brazauskas, the Lithuanian Communist leader who won the majority wing of his party over to the cause of independence. "This is about the whole of the Soviet Union. This means dictatorship in the Soviet Union."

Romualdas Ozolas, the republic's deputy prime minister, said: "What happened today is part of the last convulsions of a dying giant. It was an attempted coup supported by the military."

Inside the Lithuanian parliament hours after the broadcast center was stormed, legislators fearing a takeover of their building tonight told all loyalist guards to stop carrying their rifles to avoid giving the army an excuse to begin firing. Gas masks were distributed.

Landsbergis, a musicologist who led Lithuania to its declaration of independence, wore a bulletproof vest in anticipation of a military raid. The parliament building was packed with sandbags tonight, and the atmosphere was extremely tense.

The 10-p.m.-to-6-a.m. curfew was ordered over Lithuanian radio in the name of the National Salvation Committee, a creation of the hard-line, Moscow-backed minority wing of the republic's Communist Party. The committee and army troops ordered thousands of mourners off the streets this evening, but many people defiantly stayed outside for several hours more, carrying memorial candles and waving yellow, red and green Lithuanian flags now edged in black.

Speaking to tens of thousands of people outside the building this afternoon, Landsbergis said: "Today will determine whether we can continue on our path to independence. If they stop us today, Lithuania will carry on in the hope that it will succeed in the end. It is our duty to suffer this day, whichever way it leads us. Do not show your hatred."

Landsbergis said he tried to reach Gorbachev by phone but failed. "The gates in Moscow are closed to us," he said. "The decision has been made."

It remained unclear what role Gorbachev played in the assault. In recent months, he has assumed a hard-line stance against the Baltic states and other rebellious Soviet republics under tremendous political pressure from the military, the KGB security police and the Communist Party. He is scheduled to appear Monday before the Soviet legislature to nominate a new prime minister.

Hours before the attacks, Gorbachev and his cabinet, the Federation Council, said peaceful, political means should be used to solve the crisis in Lithuania. But Pugo said the situation had "changed" in the intervening hours. A delegation from the Federation Council, including Armenian President Levon Ter-Petrossian, a former political prisoner who spearheaded his republic's push for independence, met with Landsbergis and other leaders here.

In giving his account of the Vilnius violence, Pugo used the bureaucratic language of an earlier era as he blamed the violence on "forces in the republic seeking their ambitious goals," a clear reference to the independence-minded Lithuanian government. Pugo said troops had been forced to seize the television tower because of "provocative" broadcasts.

Pugo, the hard-line former Latvian KGB chief who replaced the more liberal Vadim Bakatin as interior minister last month, denied that the military had staged a coup to topple the Lithuanian government. He claimed instead that the rights of "a huge sector" of the republic's population was "under threat" and that the army was defending those people.

Pugo said the situation was now "under control, unless someone tries to aggravate the situation."

Tens of thousands of demonstrators in Moscow, Leningrad, Lvov, Tbilisi, Kishinev, Riga and other cities in the Soviet Union expressed their outrage at the military assaults in Vilnius.

On a march through the center of the Soviet capital, about 5,000 demonstrators cried "Down With the Murderers!" and "Gorbachev Resign!"

Outside the Winter Palace in Leningrad, where the Bolsheviks first seized power in 1917, thousands of demonstrators screamed angry slogans aimed at Gorbachev, including "Down With the Nobel Prize Winner!"

Ilya Zaslavski, a Lithuanian legislator, said Elena Bonner, the widow of the late human-rights campaigner Andrei Sakharov, has asked that Sakharov's name be removed from the list of Nobel Peace Prize winners "in order to avoid being on the same list as Gorbachev."

In Riga, the Latvian captial, where more than 100,000 people staged a rally outside the city's main cathedral in sympathy with the Lithuanians, the republic's vice president, Dainis Ivans, said he expected Soviet troops to make an assault there early Monday morning. Ivans said he had reports that more than 2,000 paratroopers were on their way to the city for an attack.

Latvian lawmaker Ivan Kezberis said: "Tragedy is just around the corner. Action is being taken all over the Baltics. I don't think anyone will escape."

In Estonia, legislators gathered for an emergency session and the Baltfax news agency reported that callers to the parliament said troops and tanks were massing on the republic's border "waiting for a command."

During the fighting here in Vilnius this morning, soldiers beat and chased some journalists and seized cameras from an NBC reporter and others. New restrictions imposed by the army include a ban on the use of tape recorders and video equipment.

At Clinical Hospital No. 1 in Vilnius, the scenes of carnage were horrific -- people with bullet wounds in the body, burned faces, crushed legs. All the city's doctors and nurses rushed to the hospital after the news of the army attack broke this morning. A stream of people arrived to donate blood.

Dalia Steibliene, the doctor on duty at the clinic when the fighting broke out, said: "My hair stood on end with some of the things I have seen tonight. We had all heard about this kind of violence in {Azerbaijan and Georgia in the past two years}, but nobody thought that anything like this would happen in peaceful Lithuania."

Correspondent David Remnick in Moscow and staff writer Don Oberdorfer in Washington contributed to this report.