WASHINGTON — President Bush today warned of a “dramatic and brutal escalation” of violence by Russia in the former Soviet republic of Georgia. He pressed Moscow to accept an immediate cease-fire and to pull back its troops.

Mr. Bush put the crisis at the top of his agenda as he returned from the Olympic Games in Beijing.

In a Rose Garden statement, he said there appeared to be an attempt by Russia to unseat Georgia’s pro-Western president, Mikhail Saakashvili.

He demanded an immediate cease-fire, the withdrawal of Russian troops from the conflict zone and a return to the status quo as of August 6.

Russia has ignored calls for a truce and has responded with overwhelming military force. It appeared Mr. Bush had little leverage to win Moscow’s compliance.

Mr. Bush said the military crackdown has “substantially damaged Russia’s standing in the world. And these actions jeopardize Russia’s relations with the United States and Europe. It is time for Russia to be true to its word and to act to end this crisis.”

Mr. Bush appeared in the Rose Garden about an hour after his return from Asia.

“I just met with my national security team to discuss the situation in Georgia. I am deeply concerned by reports that Russian troops have moved beyond the zone of conflict, attacked the Georgian town of Gori, and are threatening Georgia’s capital of Tiblisi,” Mr. Bush said.

He cited evidence suggesting that Russian forces may soon begin bombing the civilian airport in the capital city.

“If these reports are accurate, these Russian actions would represent a dramatic and brutal escalation of the conflict in Georgia,” Mr. Bush said.

He said the actions “would be inconsistent with assurances that we have received from Russia that its objectives were limited” to restoring peace in separatist pro-Russian areas.

“Russia has invaded a sovereign neighboring state and threatened a government elected by its people,” Mr. Bush said. “Such an action is unacceptable in the 21st century.”

He said the Georgian government already had accepted outlines of a peace agreement that the Russian government previously suggested it would accept.

Its terms include “an immediate cease-fire, the withdrawal of forces from the zone of conflict, a return to the military status quo as of August 6 and a commitment to refrain from the use of force,” Mr. Bush said.

Mr. Bush noted that European leaders and officials were pressing for Russia’s agreement to this peace plan.

“Russia’s government must respect Georgia’s territorial integrity and sovereignty,” the president said. “Russia’s government must reverse the course that it appears to be on as a first step toward resolving this conflict.”

“Russia’s actions this week have raised serious questions about its intentions in Georgia and the region,” the president said.