Two senior officials said it was unlikely the joint maneuvers scheduled to begin Friday would take place.

"Let us discuss it with the other participants, but I think I can say that it is hard to imagine that this would be fruitful at this time," said one of the officials, who asked to remain anonymous."

There would be a "likely withdrawal from (the) exercise," another senior official from President George W. Bush's administration confirmed to AFP.

Officials also raised questions about Russia's ongoing efforts to join the World Trade Organization and the Organization for Economic Cooperation and Development as well as its membership of the Group of Eight most industrialized nations.

"Russia has much more to lose than the Soviet Union had to lose in 1968," one of the officials briefing reporters said.

"Russia has one foot in integration into the international economy and community of states and one foot that is not quite in."

Russian President Dmitry Medvedev has outlined a series of ambitious political and economic goals, the official said, adding that in order to achieve these, "Russia is going to have to assure its integration into the WTO and the OECD and the G8 and institutions like that."

"Russia now has a lot to do" to accomplish that, the official said.

In his sharpest comments yet on the Caucuses crisis, Bush on Monday warned Moscow to end the war in Georgia, saying a "dramatic and brutal escalation" of the bloody fighting could cripple Moscow's ties to the West.

"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," Bush said at the White House.

Medvedev on Tuesday ordered a halt to Moscow's military onslaught against Georgia, but the Tbilisi government reported new attacks later in the day and there was a wary international response.

Emerging from a crisis meeting with his national security team, Bush urged Moscow to accept a Europe-backed peace plan calling for an immediate ceasefire and the pull-back of forces on all sides.

The multilateral exercises involving US, French, Russian and British naval forces were set to begin in the Sea of Japan off the Russian port of Vladivostok on Friday and continue to August 23, a US military official said.

The USS McCampbell, a guided missile destroyer, was due to participate.

It was to be the latest in a series of joint war games that began in 1988.

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