President Mikhail Gorbachev offered Thursday to unilaterally reduce Soviet short-range missiles in Europe if NATO agrees to negotiate on the tactical nuclear weapons.

"If it becomes clear that NATO countries are ready to join us in negotiations on tactical nuclear weapons, we could, naturally after consulting our allies, carry out without delay further unilateral reductions in our tactical nuclear missiles in Europe," Gorbachev said in a speech to the 23-nation Council of Europe in Strasbourg, eastern France.The 45-minute speech on Gorbachev's theme of "a common European house" marked the first time a communist head of state addressed the Council of Europe, a body set up in 1949 to safeguard ideals of common heritage and to promote economic and social development in the region.

"Facing the European parliamentarians and consequently Europe as a whole, I should like to say once again a few words about our straightforward and clear-cut positions on disarmament," Gorbachev said.

"We see the elimination of nuclear weapons as a stage-by-stage process, with the USSR remaining faithful to its non-nuclear ideals and the West to the concept of minimum deterrence," Gorbachev told the parliamentarians who make up the council.

The Soviet Union's repeated calls for early negotiations on short-range nuclear missiles have divided the NATO alliance. Britain and the United States oppose them and West Germany supports them, hoping to eliminate the weapons from Europe.

On another topic, Gorbachev said Wednesday that he is prepared to meet with Polish Solidarity's leaders and he thinks democratization based on free elections should not be confined in the East bloc to Hungary and Poland.

He also said the Soviet Union would accept governments in Eastern Europe that are no longer dominated by the Communist Party.

"The right to free election . . . is of vital importance," he said.

"How the Polish and Hungarian people decide to structure their society and their lives will be their affair," said the Soviet leader.

On the missile issue, NATO leaders meeting in Brussels, Belgium, in May urged the Soviets to unilaterally reduce short-range missile systems to the current levels of the NATO arsenals before completing the Vienna negotiations on conventional arms.