President Boris Yeltsin on Friday authorized the Russian government to use force in the breakaway republic of Chechnya, telling his Cabinet to employ "all means at the state's disposal'' against illegal armed groups there.


Defense Minister Pavel Grachev immediately left Moscow for the north Caucasus region, where Russian troops are massed around its borders, Itar-Tass said.


Yeltsin issued a decree that left little doubt he was preparing to end Chechnya's three-year defiance of Russian rule since it declared independence in 1991.


In a statement that formalized a decision taken by the Security Council last week, Yeltsin said unspecified militias in Chechnya are "causing bloodshed, taking lives and violating the rights of citizens of the Russian Federation," and he instructed the government to disarm those groups using "all means at the state's disposal."


In Chechnya, meanwhile, authorities ordered schools closed, and residents of Grozny frantically built fortifications amid rumors of an imminent assault by Russian troops on the capital.


Yeltsin stopped short of declaring a state of emergency in Chechnya. But though the language of the decree was obscure, the implications appeared to be clear.


"The government has various means at its disposal," Yeltsin's spokesman Denis Perkin told reporters. "There is the Foreign Ministry, the Defense Ministry, the Interior Ministry, all the law-enforcement bodies. The government can use all these means to carry out the president's instructions."


Chechen leaders shrugged off the latest threat from Russia.


"It would not surprise me if they brought in troops," Vice President Zelimkhan Yandarbiyev said in Grozny. "We are prepared for this."


Forces loyal to Chechen leader Dzhokhar Dudayev have shown no signs of bowing to Kremlin demands to lay down their arms.


Chechnya's main opposition forces also made clear they would defy the order to lay down their arms by vowing to resume fighting Monday, reversing an earlier decision.


The opposition Provisional Council told its fighters to take control of air space used for flights from Moscow to Grozny. It did not say how they would do so. It also told them to detain any Russian officials deemed to have made a deal with Dudayev.


"All units of the armed forces of the Provisional Council are to be in complete combat readiness by Dec. 12," said a statement signed by Beslan Gantamirov, head of the Provisional Council's armed forces.


A separate statement sent to Itar-Tass said the council would "resume military actions against Dudayev's regime" on Monday.


The statements made clear the opposition was preparing either to defy Russia's ultimatums to lay down arms or to provoke Russia to send in troops.


Grachev held talks with Dudayev in the northern Caucasus on Tuesday, and they agreed not to use force to end the crisis. But since then Russia has toughened its stance.


Thousands of Russian troops surround the republic, Russian warplanes have bombed Grozny, and Russian intelligence agents have recruited soldiers to fight Dudayev's government.


Chechnya has fiercely resisted Moscow's efforts, however, and captured a number of Russian servicemen. The last group of captives was released Thursday under a deal forged by Dudayev and Grachev. Only one soldier, too badly wounded to be moved, remains in Grozny.


The freed prisoners said they were part of a contingent of 82 Russian soldiers who manned 26 Russian tanks in a failed attack on Grozny on Nov. 26. Nineteen of the 82 were captured, they said.


Like the prisoners freed earlier, they said they had been paid and recruited by Russia's counterintelligence agency.


In Moscow, Russia's lower house of parliament, the State Duma, has been considering a draft resolution to censure Yeltsin over his handling of the crisis, and urging him not to use force.


But under pressure from State Duma Chairman Ivan Rybkin, debate on the resolution was postponed until Dec. 14.


Liberal deputies sent a telegram to Yeltsin earlier Friday saying he must be held responsible if troops go in.


"If troops are sent into Chechnya, you personally will bear responsibility for the bloodshed," the telegram said.


On Thursday the Federation Council, parliament's upper house, passed a resolution condemning Russia's covert military actions and the dispatch of regular troops to fight in Chechnya on the side of the opposition.


Residents of Grozny have been bracing for armed intervention, and many have sent their families into the countryside. The city has also experienced severe problems with heating and food supplies.


The situation worsened after a natural-gas pipeline from the neighboring southern Russian region of Stavropol was damaged Thursday in what authorities called an accident, Interfax said.


Gas supplies to Grozny have been reduced to one-third the usual level. Authorities are unsure how the pipeline was ruptured. (Reuters, AP)