VILNIUS, U.S.S.R., FEB. 9 -- Lithuanians voted overwhelmingly today in favor of seceding from the Soviet Union, delivering a historic rebuke to Soviet President Mikhail Gorbachev.

The president of the election commission announced that 90.5 percent of the votes cast in the non-binding referendum were in favor of secession and 6.6 percent against. Turnout was 84.4 percent of the 2.7 million eligible voters.

The voting in the Soviet Union's first-ever plebiscite on secession took place without incidents of violence despite fears of possible intimidation by the Soviet military, according to government officials at the barricaded parliament building. Gorbachev had denounced the referendum as illegal, claiming that the pro-independence governments in Lithuania and the other two Baltic states do not reflect the peoples' wishes.

President Vytautas Landsbergis said at a news conference after the official preliminary results were in: "The Lithuanian people reject lies, and they are not afraid. . . . This will give strength and patience to our nation; these are things we may need in the future."

The president, speaking in a packed conference hall of the parliament building, stressed that the impact of the vote would be to consolidate international support for the independence drive. In a reference to Moscow, he said, "Those who want to ignore the rights of the Lithuanian people to independence will ignore this plebiscite. But we always believe in the good will of the people of the world."

He added that the result should encourage Lithuania's Baltic neighbors to proceed with their plans for similar polls. Estonia has scheduled a March 3 referendum, and Latvia is expected to hold one soon as well.

As they voted, many Lithuanians were emotional. Brone Lusaitis, a retired worker, took his granddaughter to his polling station at a high school in the Zirmunai district of Vilnius.

At the green ballot box -- which, on its raised platform, looked like an altar -- Lusaitis hoisted the girl in his arms so she could drop his ballot inside.

"What we old people suffered -- I don't want my granddaughter to suffer the same things," Lusaitis said, his eyes filling with tears as he spoke of Lithuania's brief period of independence before its annexation by the Soviet Union in 1940.

At the same precinct, a woman presented officials with a poem she had written about freedom. Other voters brought gifts of candy, cakes and flowers for officials, who expressed surprise, saying that in previous elections it was the precinct workers who gave out gifts to lure voters to the polls.

Lithuanians looked incredulous when asked how they had voted. "For freedom, of course," one voter said, laughing at what he apparently regarded as an absurd question.

Lithuanian officials have said today's poll is just another step in their continuing battle with Moscow. They express uncertainty at how Gorbachev, the Soviet military or the KGB security police will react. Last month 13 Lithuanians were killed in a Soviet army attack widely viewed as a coup attempt backed by hard-line political forces in Moscow.

The republic's government said today that 1,400 KGB troops had arrived in Lithuania Friday and are being housed at Soviet military bases near the city of Kaunas. This came less than 48 hours after the military notified the Lithuanian government that it would start 10 days of military maneuvers in the Baltic states on Sunday.

The Soviet government is holding a nationwide referendum on March 17 in which voters will be asked whether they support a new union treaty that would keep the country's 15 republics linked in a single state. The Lithuanian government, rejecting any activities that might legitimize Soviet rule, has said it will not help organize the referendum and most Lithuanians are expected to boycott the balloting.

Nonetheless, the Soviet referendum can be staged in Lithuania, Estonia and Latvia by "social organizations," possibly including the military, according to a senior Communist Party official here. In such a poll, most of the voters would be army personnel and civilians who declined to vote in today's poll or were ineligible because they moved here after November 1989. Such voters could be expected to support Moscow in the referendum.

Moscow's hostility reflects hard-liners' fears that secession by the Baltic states would encourage independence movements in other Soviet republics.

Juozas Jarmalavicius, the chief ideologist of the pro-Moscow Lithuanian Communist Party and spokesman for the group behind last month's coup attempt, described Lithuanian President Landsbergis as a "fascist" who is destroying the republic.

The Communist Party here argues that ethnic Russians and Poles who account for about 20 percent of the population, would face severe discrimination if Lithuania seceded. Although the Baltic governments have pledged to respect minority rights, some people are worried.

"I am not sure that there won't be discrimination," said Ludmilla Triagina, an ethnic Pole who voted against independence but said Lithuania should be allowed to secede if that is what the voters want.

Special attention is being paid to the voting patterns of Lithuania's minority groups, partly because they may be a bellwether of voting in Estonia and Latvia. Minorities, mostly Russians, constitute about half of the Latvian population and about 40 percent in Estonia -- enough to leave referendum results uncertain there.

An official breakdown of minority votes here was not available because the ballots did not indicate voters' ethnic backgrounds. Turnout was reported at about 20 percent in the largely ethnic Polish town of Salcipinkai and the mainly ethnic Russian town of Snieckus, according to preliminary statistics.