MOSCOW -- The leaders of Russia, Ukraine, and Byelarus declared yesterday that the Soviet Union had ceased to exist and proclaimed a new Commonwealth of Independent States open to all states of the former union.
In a series of statements issued after a two-day meeting at a Byelarussian government retreat, the leaders of the three Slavic republics declared void all efforts to create a new union on the ruins of the old one. But they called for the creation of new "coordinating bodies" for defense, foreign affairs and the economy that would have their seat in Minsk, the capital of Byelarus, and decided to maintain the ruble as their common currency.
They declared that the "norms" and activities of the former union had ceased at the moment the commonwealth agreement was signed and that the new commonwealth had assumed all international obligations of the Soviet Union, as well as control over its nuclear arsenal.
"The U.S.S.R., as a subject of international law and geopolitical reality, is ceasing its existence," the three leaders declared.
The action essentially stripped Soviet President Mikhail S. Gorbachev of his office and authority, and the immediate question was whether the tough and tenacious Soviet leader would resist and, if he did, whether the military or other centers of power would support him.
The three co-founders of the new commonwealth -- President Boris N. Yeltsin of Russia, President Leonid M. Kravchuk of Ukraine and Stanislav Shushkevich, chairman of the Byelarussian Parliament -- were scheduled to meet today with Mr. Gorbachev and with Nursultan A. Nazarbayev, the president of Kazakhstan and the unofficial spokesman for the Muslim republics of Central Asia.
Mr. Gorbachev had no immediate reaction, but in a taped interview with a French television station broadcast yesterday, he argued that dismantling the union spelled disaster and that the consequences would make the war in Yugoslavia "a simple joke by comparison."
The Central Asian republics had all indicated an interest in retaining some form of union, and it was not immediately clear why Mr. Nazarbayev was excluded from the commonwealth declaration or how he would respond.
In their declarations, the three predominantly Slavic republics said they drew their authority to dissolve the union from the fact that they were its co-founders. They and the Transcaucasian republic, later divided into Georgia, Armenia and Azerbaijan, were co-signers of the original 1922 treaty that created the Union of Soviet Socialist Republics.
The "sphere of joint activity" assigned to the new commonwealth resembled closely the functions that Mr. Gorbachev had been seeking for his new "Union of Sovereign States": foreign policy, development of a "common economic space," customs and "migratory policy," transportation and communication systems, the environment and the battle against organized crime.
One major difference was that the three Slavic republics, which together account for 73 percent of the population and 80 percent of the territory of the Soviet Union, were inviting other republics to join, not to negotiate, a new association.
It was a stance certain to irritate the Muslim and Transcaucasian republics, but also one that stood to curtail the endless bickering that has characterized negotiations among the republics since the failed August coup.
Another major difference was that the move to Minsk and the formal disbanding of the old union cleared the slate of old structures and bureaucracies, freeing the participating republics of the need to haggle with Mr. Gorbachev and the old ministries over the new order they meant to shape.
But the approach has its own dangers. Besides Mr. Gorbachev, other potential sources of resistance include the potent military-industrial complex and the trade unions, which could feel threatened by their transfer to new masters dedicated to reducing the budget.
Resistance also could come from republican parliaments and nationalist movements, especially in Ukraine, which might see in the agreement a trick to revive the old union in a new guise.
Yet the commonwealth appears to be the most practical compromise available for the republic leaders. It disassociates the new commonwealth from Moscow, creates a core made up of the most important republics and blocks the disintegration that threatened to destroy critical economic ties among the republics.
The commonwealth agreements touched on the major areas of concern in the three republics. They called for coordinated economic reforms, echoing fears in Ukraine and Byelarus that the impending reforms in Russia could create havoc with their prices.
They declared the ruble to be the currency of common commerce, and they called for mutual agreement before the introduction of any new currency, responding to Russia's fear that a separate currency in Ukraine could flood Russia with excess rubles.