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The Bush administration may have ceded mediation duties between Russia and Georgia to Europe but is holding firm to its support for Georgia's pro-Western leadership and demands that Moscow withdraw its troops from the former Soviet republic.

While waiting for the results of a European Union initiative led by French President Nicholas Sarkozy, the administration and its allies also are debating ways to punish Russia for its invasion of Georgia, including expelling Moscow from an exclusive club of wealthy nations and canceling an upcoming joint NATO-Russia military exercise.

Although mainly focused on securing a truce and dealing with Georgia's urgent humanitarian needs after five days of fierce fighting that may have killed 2,000 people, U.S. officials already are looking to next steps, including the pullout of Russian soldiers and new peacekeeping missions in the flashpoint separatist areas of Abkhazia and South Ossetia.

Click here to view photos of the conflict in Georgia.

"It is very important now that all parties cease fire," Secretary of State Condoleezza Rice said Tuesday. "The Georgians have agreed to a cease-fire. The Russians need to stop their military operations, as they have apparently said that they will. But those military operations really do now need to stop because calm needs to be restored."

A senior U.S. official, speaking on condition of anonymity to describe confidential high-level diplomatic conversations, said European and other leaders have been blunt with Russia that it must withdraw. Russia insists it does not plan a long-term occupation, the official said, but it isn't clear whether Russia has offered a timeline for withdrawal.

"People are saying, 'You know, you cannot stay,"' the official said. "We have been hearing from Russia, 'We don't want to stay."'

Yet as they pursue those efforts, President Bush and his top aides are engaged in urgent consultations with European and other nations over how best to demonstrate their fierce condemnation of the Russian operation that began in South Ossetia, expanded to Abkhazia and ended up on purely Georgian soil.

"The idea is to show the Russians that it is no longer business as usual," said one senior official familiar with the consultations among world leaders and at lower levels, notably at NATO headquarters in Brussels. Alliance diplomats there met together and then with representatives of Georgia on Tuesday.

The U.S. boycotted a third meeting at NATO on Tuesday at which the alliance's governing board, the North Atlantic Council, was to prepare for as-yet unscheduled talks with a Russian delegation called at Moscow's request, officials said.

In addition, a senior defense official said the U.S. has decided to dump a major NATO naval exercise in the North Pacific with Russia that was scheduled to begin Friday. Sailors and vessels from Britain, France, Russia and the U.S. were to take part in the annual Russia-NATO exercise aimed at improving cooperation in maritime security. But the official said there was no way the U.S. could proceed with it in the midst of the Georgian crisis.

The naval exercise began a decade ago and typically involves around 1,000 personnel from the four countries, officials said. The Pentagon also is looking at a variety of ways it could respond to humanitarian needs in Georgia, but officials have not yet made any final decisions.

In the medium term, the United States and its partners in the Group of Seven, or G-7, the club of the world's leading industrialized nations that also includes Britain, Canada, France, Germany, Italy and Japan, are debating whether to effectively disband what is known as the G-8, which incorporates Russia, by throwing Moscow out, the officials said.

Discussions also are taking place on whether to revoke or review the May 2007 invitation to Russia to join the 30-member, Paris-based Organization for Economic Cooperation and Development, which consists primarily of established European democracies, the officials said, adding that Russia's pending membership in the World Trade Organization might also be affected.

The officials spoke on condition of anonymity because no decisions have yet been made and consultations with other countries involved were still under way.