President George W. Bush on Monday demanded that Russia end a "dramatic and brutal escalation" of violence in Georgia, agree to an immediate cease-fire and accept international mediation to end the crisis in the former Soviet republic. Almost immediately after his return from the Olympics in China, Bush warned Russia in his strongest comments since the fighting erupted over Georgia's separatist South Ossetia region last week to "reverse the course it appears to be on" and abandon any attempt to topple Georgia's pro-western government. "Russia has invaded a sovereign neighboring state and threatens a democratic government elected by its people. Such an action is unacceptable in the 21st century," the president said in a televised statement from the White House, calling on Moscow to sign on to the outlines of a cease-fire as the Georgian government has done. "The Russian government must reverse the course it appears to be on and accept this peace agreement as a first step toward solving this conflict," Bush said, adding that he is deeply concerned that Russia might bomb the civilian airport in the capital of Tbilisi. He said Russia's escalation of the conflict had "raised serious questions about its intentions in Georgia and the region" and had "substantially damaged Russia's standing in the world." "These actions jeopardize Russia's relations with the United States and Europe," Bush said. "It's time for Russia to be true to its word to act to end this crisis." Despite the tough talk, the president's comments were not backed up by any specific threat of consequences Russia might face if it ignores the warning. US officials said they were committed to the diplomatic track and were working with US allies in Europe and elsewhere, as well as with the Russians, to defuse the crisis. Earlier Monday, the United States and the world's six other largest economic powers issued a call similar to Bush's for Russia to accept a truce and agree to mediation as conditions deteriorated and Russian troops continued their advances into Georgian territory. Secretary of State Condoleezza Rice and her colleagues from the Group of Seven leading industrialized nations pledged their support for a negotiated solution to the conflict that has been raging since Friday, the State Department said. "We want to see the Russians stand down," deputy spokesman Robert Wood told reporters. "What we're calling on is for Russia to stop its aggression." Rice and the foreign ministers of Britain, Canada, France, Germany, Italy and Japan spoke in a conference call, during which they noted that Georgia had agreed to a cease-fire and wanted to see Russia sign on immediately, he said, adding that the call was one of more than 90 that Rice has made on the matter since Friday. They called on Russia to respect Georgia's borders and expressed deep concern for civilian casualties that have occurred and noted that Georgia had agreed to a cease-fire and said the ministers wanted to see Russia sign on immediately as urgent consultations at the United Nations and NATO were expected, according to Wood. The seven ministers backed a nascent mediation efforts led by French Foreign Minister Bernard Kouchner, whose country currently holds the rotating presidency of the European Union, and Finnish Foreign Minister Alexander Stubb, whose country now holds the chair of the Organization for Security and Cooperation in Europe, he said. The Group of Seven, or G7, is often expanded into what is known as the G8, a grouping that includes Russia, but Russian Foreign Minister Sergey Lavrov was notably not included in the call. Wood said the United States was hopeful that the UN Security Council would pass a "strong" resolution on the fighting that called for an end to attacks on both sides as well as mediation, but prospects for such a statement were dim given that Russia wields veto power on the 15-member body. A senior US diplomat, Matthew Bryza, is now in Tbilisi and is working with Georgian and European officials there on ways to calm the situation. Meanwhile, the State Department said it has evacuated more than 170 American citizens from Georgia. Wood said two convoys carrying the Americans, along with family members of US diplomats based in Georgia, left Tbilisi on Sunday and Monday for neighboring Armenia. The US Embassy in Georgia has distributed an initial contribution of $250,000 in humanitarian relief to victims of the fighting and is providing emergency equipment to people in need, although those supplies would run out later Monday, the department said. The Pentagon said it had finished flying some 2,000 Georgian troops back home from Iraq on C-17 aircraft at Georgia's request. It said it had informed the Russians about the flights before they began in order to avoid any mishaps, but Russian Prime Minister Vladimir Putin harshly criticized the step, saying it would hamper efforts to resolve the situation by reinforcing Georgian assets in a "conflict zone." Wood rejected the criticism, saying: "We're not assisting in any conflict." Defense Department spokesman Bryan Whitman said the US flew the Georgians out of Iraq as part of a prior agreement that transport would be provided in case of an emergency. Pentagon officials said Monday that US military was assessing the fighting every day to determine whether less than 100 US trainers should be pulled out of the country. There had been about 130 trainers, including a few dozen civilian contractors, but the civilians had been scheduled to rotate out of the country and did so over the weekend, Whitman said. The remaining uniformed trainers were moved over the weekend to what officials believe is a safer location, he said.