Crimea's local parliament voted unanimously to join Russia and announced a regional referendum in the Ukraine peninsula to decide the matter March 16, moves that have intensified the worst post-Cold War crisis between Moscow and the West.
NATO, using some of its strongest language yet, publicly assured Ukraine's interim Prime Minister that it stands by the "territorial integrity" of his country.
The United States also deployed six more jets to patrol Baltic states that are increasingly nervous about the invasion of Crimea, home to an ethnic Russian majority and now effectively under Russia's control.
High-stakes diplomatic efforts continued, although with little sign of easing international tensions or allaying fears of a breakup of Ukraine. Later Thursday, U.S. President Barack Obama spoke by telephone for an hour with Russian President Vladimir Putin. It was their second extended conversation about Ukraine in six days.
Separately, as part of its protest against Moscow's seizure of Crimea, Canada expelled nine Russian soldiers taking part in military exercises in this country.
A source said one Russian soldier was located in Gatineau, Que., two were at Canadian Forces Base Gagetown in New Brunswick and six were in Saint-Jean, Que.
The White House, in a statement, said Mr. Obama urged Mr. Putin to send Russian troops back to their bases in Crimea, allow international monitors in to ensure the rights of ethnic Russians are respected and consent to direct talks with Ukrainian officials. There was no word on Mr. Putin's response.
The U.S., Canada and the EU rejected the Crimean referendum as illegitimate, saying no ballot can have validity while Russia is occupying Crimea with a military force. Mr. Obama said the ballot "would violate the constitution and violate international law."
Prime Minister Stephen Harper said Crimea is under "illegal military occupation," termed Russia's invasion of the peninsula as an act of aggression, and said Canada will not recognize the upcoming referendum.
The Prime Minister says he views the situation in Ukraine "with the gravest concern" and will co-operate with its G7 partners and like-minded allies.
Another dozen U.S. warplanes, meanwhile, will arrive for a training exercise in Poland next week as former Soviet satellite states grow ever more worried about Moscow's territorial ambitions. The U.S. Navy also said a guided-missile destroyer, the USS Truxton, is heading to the Black Sea in what it said was a long-planned training exercise and not a show of force. This would put the warship in close proximity to Crimea.
"Russia today is dangerous," Lithuanian President Dalia Grybauskaite told journalists at an emergency summit of European Union leaders in Brussels. "After Ukraine will be Moldova, and after Moldova will be different countries. They are trying to rewrite the borders after the Second World War in Europe."
A senior U.S. official, speaking on background, said the Baltic overflights and reinforcement of U.S. military operations in Poland are meant to "reassure our Eastern European allies that at this very delicate and potentially destabilizing time, the United States is strongly committed to their security."
The separatist push by pro-Moscow forces in Crimea, where Russia's Black Sea fleet has been based since 1783, came as European leaders tried to find ways to unwind the crisis that has escalated since pro-Western opposition forces ousted Viktor Yanukovych as Ukraine's president last month. Mr. Putin then moved military forces to Crimea in what he has termed a "humanitarian" mission to protect ethnic Russians in the eastern part of the country.
Ukraine's interim Prime Minister Arseniy Yatsenyuk rejected the Crimea referendum announcement, calling the regional lawmakers merely a "so-called government" and urging Mr. Putin to end support for the separatists. "Tear down this wall, the wall of intimidation, of military aggression," he said in Brussels, following talks with EU leaders. "We are ready for co-operation, but we are not ready to surrender and be the subordinate of Russia."
NATO Secretary-General Anders Fogh Rasmussen, standing beside Mr. Yatsenyuk, called Russian aggression in Crimea "the gravest threat to European security since the end of the Cold War" and warned Moscow against claiming Crimea. "There should be no attempt to draw new lines on the map of Europe in the 21st century," Mr. Rasmussen said.
EU leaders, divided on how to respond, agreed to suspend talks with Moscow on visas and a new investment pact while warning of tougher action if there is no negotiated solution within a short period. Mr. Obama, however, issued an executive order slapping new visa restrictions on Russian and other opponents of Ukraine's interim government. A U.S. official said Mr. Putin was not on the list of those to be sanctioned.
The Russian news agency RIA Novosti reported the Russian military is conducting drills involving more than 3,500 troops at its southern testing range of Kapustin Yar, about 450 kilometres east of the Ukrainian border. In Crimea, Russian and pro-Russia militias have blockaded or seized all Ukrainian military facilities. The city council of Crimea's port city of Sevastopol, home to a sprawling Russian naval base, followed the Crimean regional parliament in voting Thursday to join Russia and break all links with Ukraine.
With reports from the Canadian Press, Associated Press and Reuters