THE BOSNIA DILEMMA : Yeltsin Warns Serbs to Stop Attacks : Russia: The Kremlin leader’s sharply worded statement shows shift in attitude toward longtime allies.

Russian President Boris N. Yeltsin on Tuesday warned the Bosnian Serbs to keep their promises to Russia and stop attacking Muslim civilians trapped in the U.N. safe area of Gorazde in Bosnia-Herzegovina.

Yeltsin’s sharply worded statement was a sign that Russia’s patience with its traditional Serbian allies is wearing thin, as what appeared to be a major foreign policy triumph by a resurgent Moscow turns into an embarrassing rout for Russian diplomacy.

“The Bosnian Serb leadership must fulfill its promises given to Russia, stop the attacks and withdraw from Gorazde . . . enable the introduction of U.N. forces in the area and unblock the U.N. personnel in Bosnia and Herzegovina,” said Yeltsin’s statement, distributed late Tuesday by the semiofficial Itar-Tass news agency.

But Yeltsin’s statement fell far short of endorsing air strikes by the North Atlantic Treaty Organization on rebellious Serbian armies that are menacing Gorazde and Sarajevo, the Bosnian capital.

On Monday, Yeltsin’s special envoy to the former Yugoslav federation, Deputy Foreign Minister Vitaly S. Churkin, said a group of Bosnian Serb extremists had “fallen ill with the madness of war” and had broken cease-fire promises made to Moscow. Churkin said he had reversed his previous stance and would now recommend to his superiors that Russia support “energetically” new NATO air strikes.

Yeltsin’s statement said the international community must do its best to achieve a political settlement of the Bosnian crisis. He called for a summit on Bosnia that would include officials from Russia, the United States, the European Union and the United Nations.

Earlier in the day, Yeltsin spoke by telephone with German Chancellor Helmut Kohl. The Kremlin leader told Kohl that “Russia made and is making the maximum effort to prevent the escalation of the crisis around the city of Gorazde,” but to no avail.

“The Bosnian Serbs do not keep their word,” Yeltsin said, according to Itar-Tass.

Russian Foreign Minister Andrei V. Kozyrev, still stinging from the betrayal, warned the Bosnian Serbs to “stop taxing the patience of the world community.”

The Russian Security Council will meet today to discuss the Bosnian crisis. A closed session of the Duma, the lower house of the Russian Parliament, will also be held today.

But snubbing or punishing the Bosnian Serbs or their allies in Serbia could prove politically risky. Neo-fascist lawmaker Vladimir V. Zhirinovsky has championed their cause, and public opinion remains sympathetic.