MOSCOW, DEC. 11 -- The leadership of the Georgian Soviet republic declared a state of emergency in the region of South Ossetia today, saying that three people had been killed there in ethnic violence.

Political leaders in South Ossetia have long wanted to unite with North Ossetia, a neighboring, ethnically linked region that is included in the Russian republic. As a way to head off that movement, the Georgian legislature on Tuesday abolished South Ossetia as an autonomous entity and declared it a part of Georgia.

Georgian television gave no details on the violence in the South Ossetian capital, Tskhinvali, except to say that a "terrorist act" led to three deaths.

Supreme Soviet Chairman Anatoli Lukyanov said Georgia's decision to put the region under the control of the government bodies in Tbilisi was a violation of the Soviet constitution, and he appealed to the republic's legislators to "rethink" their votes.

The Georgian legislature, led by President Zviad Gamsakhurdia, declared a curfew in South Ossetia and said Interior Ministry and KGB troops would patrol the area. The autonomous region, with a population of 100,000, has been in conflict with Georgians for two years. Last January, Interior Ministry troops had to put down sporadic gun battles between Ossetians and Georgians.

The conflict is part of a vast mosaic of ethnic struggle across the Soviet Union, and the central authorities in Moscow are showing signs of exerting greater pressure on nationalists to give up their demands for outright independence.

Lukyanov told reporters that the Congress of People's Deputies, the country's highest legislative body, which begins a week-long session on Monday, could call for a nationwide referendum on the preservation of the union.

The political strategy for such a referendum, from Soviet President Mikhail Gorbachev's point of view, is clear: its likely passage would put greater pressure on the three Baltic republics, Georgia, Armenia and Moldavia to put off their demands for independence.

Gorbachev has argued that unless the 15 republics sign his new Treaty of the Union, the country would be in danger of collapse and face the possibility of civil war.

Next week's Congress is expected to pass a new law outlining the regulations for national referendums. Lukyanov said the Congress would also consider "conceptual" questions of the draft of the union treaty. The Balts and Georgians already have said they would not sign the treaty and even the leader of Kazakhstan, a relatively conservative republic, said he would not sign unless the document gave the republics "clearer control" over their own resources and economic ties.