MOSCOW -- Pressure grew yesterday for the resignation of the government of Prime Minister Nikolai I. Ryzhkov, as republican leaders and parliamentarians demanded that power be transferred to the 15 Soviet republics and Moscow's massive ministerial bureaucracy be replaced with a coordinating committee.
They spoke at an emergency session of the Supreme Soviet that saw a direct clash of the country's two great political rivals, Soviet President Mikhail S. Gorbachev and Russian leader Boris N. Yeltsin. Their face-off contributed to a growing sense that the country's political crisis is reaching its culmination.
In an emotional, 90-minute speech, Mr. Gorbachev argued that the existing, centralized power structure should be preserved until a union treaty could be signed by the republics as the basis of a new Soviet federation.
He asked for a moratorium on republican laws and other acts that might cause conflict with the Soviet government, saying that "otherwise, we'll be paralyzed and won't be able to overcome the paralysis."
"The role of the Soviet Union in the world and its responsibility for the course of international development are great," Mr. Gorbachev said. "We cannot reconcile ourselves to separatists' attempts to turn the union into a flabby entity devoid of a single will -- or even to dismember it."
But Mr. Yeltsin replied with a concentrated blast at the old system, saying the current chaos was an inevitable "crisis of the totalitarian system that still exists to this day."
He said the Ryzhkov government's determination to preserve its power at any cost was not a source of stability but a cause of instability, producing constant conflict with republican authorities. He advised Mr. Gorbachev to "stop clinging to the old system" symbolized by Mr. Ryzhkov.
Mr. Yeltsin said the government should be replaced within the next few weeks by an Extraordinary Anti-Crisis Committee consisting of representatives of all the republics. Only respect for the sovereign rights of the republics could end political paralysis and preserve any kind of union, he said.
"If there's any doubt, we can quickly organize a referendum, and then the people's opinion will become perfectly clear," he said.
Mr. Gorbachev's speech drew some backing from representatives of Central Asia and the small autonomous republics within the Russian Federation.
But most deputies appeared deeply disappointed by a speech they saw as containing little that was new. Some republican representatives -- notably those of Georgia and Latvia -- defied the president by stating flatly that their republics would not sign any union treaty and would not stay in even a reformed union.
Byelorussian Prime Minister Vyacheslav Kebich said the union already existed only on paper. "We have to look truth in the eyes: Today not a single republic will give up its sovereignty," he said.
"There was nothing new and constructive in the speech of the president," said Armenian deputy Genrikh S. Igityan.
Leningrad Mayor Anatoly A. Sobchak said the eagerly awaited speech did not offer "what people were waiting for -- a clear-cut plan for getting out of the crisis." He said chaos had resulted from the fact that centralized power in Moscow was incompatible with real republican sovereignty.
Mr. Sobchak, a lawyer often mentioned as a candidate to head a coalition government, sketched his own program on what he said were the four most serious problems: food shortages, stabilization of the ruble, land reform and privatization of commerce and industry.
The clarity and political sensitivity of Mr. Sobchak's and Mr. Yeltsin's 10-minute speeches contrasted with the rambling, largely familiar speech of the Soviet president.
Mr. Yeltsin appealed to the half of the Soviet population in the non-Russian republics by emphasizing their right to self-determination and state sovereignty. He appealed to nearly everybody by stressing the critical food situation, saying aid should be sought from the West and strategic food supplies that were stored for a future war should be opened and distributed.
At root, the emergency session of parliament, which continues today, is not based on the Gorbachev-Yeltsin rivalry but on a political paradox.
Mr. Gorbachev has maintained that both the Soviet Union and its 15 constituent republics can simultaneously be sovereign states. But the resulting attempt of the republics to exercise their sovereignty has been rebuffed by Mr. Gorbachev and the Soviet government, by actions ranging from the oil blockade of Lithuania to a recent decree banning local authorities from dismantling statues of V. I. Lenin.
With the strength offered by numbers -- nearly all the republics have now elected new parliaments and declared some form of sovereignty -- the republics are directly confronting Mr. Gorbachev.