Moscow faced growing isolation Sunday as the world's seven leading industrialized democracies and the major Western military alliance collectively condemned Russian aggression in Ukraine.
The G-7 nations of the United States, Japan, France, Germany, Italy, Britain and Canada issued a statement Sunday evening, saying they were putting on hold their plans to participate in a summit that had been planned for June in Sochi, Russia.
Russia joined the powerful group in 1998, turning it into the G-8 organization, and has planned to host the other seven members in Sochi, site of the recently completed 2014 Winter Olympics.
"We note that Russia's actions in Ukraine also contravene the principles and values on which the G-7 and G-8 operate," the seven original members said in a joint statement. "As such, we have decided for the time being to suspend our participation in activities associated with the preparation of the scheduled G-8 Summit in Sochi in June, until the environment comes back where the G-8 is able to have a meaningful discussion."
The decision essentially freezes Russia out of a group it eagerly sought to join before 1998 and increases its isolation on the world stage.
The G-7 nations added in the statement: "We are united in supporting Ukraine's sovereignty and territorial integrity, and its right to choose its own future."
Beyond the diplomatic pressure, however, it remained unclear what the Western powers and Japan could do to compel Moscow to reverse course.
NATO, meanwhile, released its own statement expressing "grave concern" over the Russian Parliament's authorization Saturday of the use of military force in Ukraine.
"NATO allies will continue to support Ukrainian sovereignty, independence, territorial integrity and the right of the Ukrainian people to determine their own future, without outside interference," NATO said in the statement.
The North Atlantic Treaty Alliance, originally formed in 1949 with the United States and 11 European nations, has expanded to include 28 member countries, including 12 that were part of the Soviet Union or tied to the broader Soviet bloc before the Soviet Union collapsed in 1991.
"We call on Russia to de-escalate tensions ... to withdraw its forces to its bases and to refrain from any interference elsewhere in the Ukraine," NATO chief Fogh Rasmussen said Sunday in Brussels.
Canadian Prime Minister Stephen Harper announced that he had recalled his government's ambassador to Russia to protest Moscow's moves in Ukraine.
Secretary of State John Kerry planned to visit Kiev on Tuesday to show his support for a fledgling pro-democracy government being formed to replace deposed Ukrainian President Viktor Yanukovich.
Yanukovich fled Ukraine last week in the face of massive demonstrations against his rule. He surfaced Friday in the southern Russian city of Rostov-on-Don, decrying his opponents as "young neo-fascists."
Ukraine placed its military on high alert and appealed for international help against what it feared was a wider Russian invasion.
"We believe that our Western partners and the entire global community will support the territorial integrity and unity of Ukraine," Ukrainian Prime Minister Arseniy Yatsenyuk said.
Operating from its Russian Black Sea Fleet military base in Sevastopol, 450 miles south of the Russian border, Moscow on Sunday gained effective control of the Crimean Peninsula, a region of western Ukraine with a high concentration of ethnic Russians.