VILNIUS, U.S.S.R., JAN. 13 -- Lithuanian leaders say they are convinced that this weekend's army assault here was an elaborately planned operation to remove the democratically elected Lithuanian government and that the outline of the plan was probably known well in advance toPresident Mikhail Gorbachev.

"Once the infernal machine of state repression has started, it becomes very difficult to stop," said Lithuanian Deputy Prime Minister Algirdas Brazauskas, the Communist Party leader here who steered the republic through earlier confrontations with Moscow over Lithuania's declaration of independence last March.

"This was all cooked up on the second floor of the Communist Party building in Vilnius," he said, referring to the site where the pro-Moscow wing of the Lithuanian Communist Party is headquartered.

"That Gorbachev allowed this to happen is as clear as 2 times 2," said Romualdas Ozolas, the Lithuanian deputy prime minister in charge of security issues.

"Gorbachev sees the problem of Lithuania in the context of the Soviet Union," Ozolas said. "He wanted to restore order, and we stood in his way. He undoubtedly knew what was being planned, although I assumed that he hoped that there would not be so much bloodshed."

A detailed reconstruction of events leading up to this weekend's crackdown, based in part on partisan Lithuanian sources, suggests that Gorbachev must have been well aware of the planning for military action in Lithuania, which left at least 13 dead and 140 wounded.

A more pertinent question is whether he willingly approved the use of paratroops against unarmed demonstrators or had no choice but to stand by as hard-liners in the Soviet leadership seized the initiative.

Gorbachev's did not appear in public today, and his actual role in the events was not known. On Thursday, the Soviet leader accused the Lithuanian leadership of "flagrant violations and deviations" from the Soviet constitution and of following a "policy aimed at restoring a bourgeois system." He said the Lithuanian people were "demanding the imposition of presidential rule" and demanded that the Soviet constitution be honored.

Although Gorbachev issued no statement today, the hard-line Soviet interior minister, Boris Pugo, went on national television and accused independence demonstrators in Lithuania of provoking the violence. Pugo denied the military had staged a coup to topple the Lithuanian government and said the army had acted to protect people "under threat" in the republic.

According to Kazimiera Prunskiene, the former Lithuanian prime minister who met Gorbachev last week in an attempt to forestall the crackdown, "There is a widely shared view here that Gorbachev is increasingly under the influence of the Communist Party . . . that he is no longer his own man."

She said that in their meeting, Gorbachev told her: "Go back home and restore order. Otherwise I will be obliged to do the job myself."

The roots of this weekend's events in the Lithuanian capital go back to at least last month when KGB chief Vladimir Kryuchkov, in a major policy change, told the Soviet Congress of People's Deputies that the Kremlin no longer felt obliged to rely on political means alone to solve the country's problems.

Kryuchkov said that in some extreme cases, it would be necessary for the authorities to rely on force to impose their will, even at the risk of bloodshed. The evidence is that he was speaking with Gorbachev's approval.

The detailed planning that went into this weekend's military action can be demonstrated by looking at the events during the 48 hours that began with the seizure by troops of the republic's newspaper publishing plant in Vilnius early Friday. Soviet officials have given a different version of these events.

Friday morning: Less than 24 hours after Gorbachev warned the Lithuanian leadership that it must return to the Soviet constitution or face the consequences, paratroops firing automatic weapons break into the printing plant. A similar operation occurred earlier this month in the Latvian capital, Riga.

Gorbachev refuses to take two calls from Lithuanian President Vytautas Landsbergis, who sought to protest the attack on the printing plant. Soviet armed forces chief of staff Gen. Mikhail Moiseyev calls off a planned meeting with Lithuanian defense officials in Moscow.

The Russian nationalist organization Yedintsvo ("Unity"), which is closely allied to the pro-Moscow wing of the Lithuanian Communist Party, forces the closure of Vilnius airport. A few hours later, Soviet troops stop all railroad traffic to Vilnius. The essential means of communication are now controlled by pro-Moscow forces.

Friday evening: The pro-Moscow Communist Party announces the formation of a Committee of National Salvation. The names of the members are not revealed, ostensibly for their own protection.

Several dozen factories, whose mainly ethnic-Russian workers are strongly influenced by Yedintsvo, demand that Gorbachev declare direct presidential rule in the republic. According to intelligence information obtained by Ozolas, a National Salvation Committee leader tells his associates: "We act tomorrow. It's now or never."

Saturday morning, about 3 a.m.: Soviet troops seize a special police academy for the training of an anti-terrorist squad. Until now, the 140-man unit has been under the control of the Lithuanian government and constitutes its most effective military weapon. Fifteen members of the unit defect to the paratroops. The weapons of the remainder are impounded.

8 a.m.: Brazauskas tries to call local military leaders and Kremlin politicians in an attempt to avert violence. A Communist Party veteran, he is on first-name terms with many of them. The Baltic military commander tells him he knows nothing about the blockade of the railroad. KGB chief Kryuchkov promises to relay a message to Gorbachev and get back to him, but never does.

Saturday afternoon: At a top-level meeting in Moscow, Soviet Defense Minister Dmitri Yazov and Interior Minister Pugo, who is the former head of the Latvian KGB, sharply condemn Lithuanian actions. Most of the Lithuanian leaders present condemn the military moves in Vilnius. The meeting ends with a call for the crisis to be resolved by "political methods."

5 p.m.: Military leaders in Vilnius appear at an unusual press conference. Gen. Vlad Uskopchik, one of the participants, says, "We have as many forces here as we need to retain order." Asked whether he is loyal to the Lithuanian government or to the Committee for National Salvation, he refuses to reply. "That is a political question," he says. Less than 12 hours later, Uskopchik is named military commandant of Vilnius.

Sunday, 1:55 a.m.: Soviet troops storm the television transmitting tower in Vilnius, firing at peaceful demonstrators who try to oppose them. Vaclovas Buzas, a 60-year-old pensioner, is shot in the hip, the first casualty. As the troops crash through the plate-glass entrance, the tower's defenders jump out the window. Another Lithuanian is shot in the back.

Reporters see a tank drive through a human chain of about 30 people, crushing to death at least one demonstrator. Other demonstrators hang onto the tank with their hands. Fighting around the TV tower continues for 80 minutes as troops fire at youths who taunt them with shouts of "Fascists" and "Occupiers." Army loudspeakers say that "all power in Lithuania" has passed to the hands of the Committee for National Salvation.

Five minutes later, another armored column attacks the television station in Vilnius, which has been broadcasting nonstop reports on Lithuania's struggle with Moscow. Similar tactics are used. Tanks fire deafening blanks to frighten the crowds as paratroops go in with tear gas and rifle fire. The windows of all the neighboring buildings are blown out by the blasts.

4 a.m.: Legislators gather in the chamber of the Lithuanian parliament. A resolution is adopted transferring executive power to the Lithuanian foreign minister, who is traveling in Europe, if the parliament building is occupied. Lawmakers pay a silent tribute to the first casualties of Lithuania's 10-month-long struggle to restore its pre-World War II independence.

5:30 a.m.: Lithuanian officials confer in the darkened halls of the government building, 500 yards away. Newly appointed Prime Minister Albertas Simenas is missing. The atmosphere is calm, but tinged with regret and bitterness. "This is the end of the illusions of even the biggest optimists," Ozolas says.

"It's the collapse of everything we once believed in: of perestroika, of the common European home, of all the talk about the self-determination of nations," says Prunskiene, a former Communist.

7 a.m.: Landsbergis, who has been unable to reach Gorbachev on the phone, issues a direct video appeal to the Soviet leader: "Mr. President, why are you covering the action of murderers with your name? If you could stop them, why haven't you? Your country is going into a terrible collapse that could drag the whole world down with it. Why do you need this?"

Speaking later to a reporter, Landsbergis waves his hand in disgust and says, "The Americans have sold us out." When asked what President Bush should do to help Lithuania, he responds: "He should ring Gorbachev on the hotline and tell him that, whatever the situation in the Persian Gulf, murder in Lithuania is also murder. If Gorbachev doesn't stop this, then nobody will defend Gorbachev from his own murderers. He will be a zero for the West and a zero for his colonels."

10 a.m.: A Roman Catholic Mass is held in Independence Square for the tens of thousands of Lithuanians forming a human shield around the parliament building. When the Mass is over, volunteers begin erecting barricades around the square to defend it from tanks.

Speaking slowly and calmly, a 53-year-old engineer, Algis Kriagzde, says he has come to defend Lithuania's first democratically elected parliament in half a century. "Your president Reagan called the Soviet Union an empire of evil. I have something to add to that: This is an empire of evil, hatred, lies, and everything that reflects the worst side of humanity."

Sunday, 7:30 p.m.: Inside the Lithuanian legislature, the atmosphere is tense and claustrophobic and becomes even more so as the 10 p.m. curfew -- the deadline set by the military to vacate the building -- approaches.

"If the military attacks, we're going to become human torches," whispers one of the legislators, Jonas Laucys. "Look at all this wood and fabric. This building was not built to be defended. It's an administrative building."

As the minutes tick away, the Lithuanian legislators debate whether to leave the area. "Let's all leave and come back tomorrow. It'll be a normal working day," shouts one hopefully. "Enough blood has been shed already," says another. "We must ask the people what they want," says a third.

As the clock on the wall marks 9:20 p.m., Landsbergis asks everyone to go home except members of the Presidium, the executive body of the legislature. "You have done your duty," he tells the crowds massed outside. "We are a free people."

9:45 p.m.: Laucys, with tears in his eyes, says: "What we just heard was a farewell speech."