U.S. President Barack Obama turned up the pressure on his Russian counterpart, insisting that President Vladimir Putin is courting the rejection of the international community by keeping soldiers on the ground in Crimea, the Ukrainian region that is scheduled to hold a referendum on severing ties with Kiev this weekend.
Mr. Obama's support for Ukraine was magnified by the presence at his side of Arseniy Yatsenyuk, the country's interim prime minister, who was welcomed at the White House only weeks after the overthrow of Viktor Yanukovych.
"The issue now is whether or not Russia is able to militarily dominate a region of somebody else's country, engineer a slap-dash referendum, and ignore not only the Ukrainian constitution, but a Ukrainian government that includes parties that are historically in opposition with each other, including by the way the party of the previous president," Mr. Obama said Wednesday.
Russia's leaders also heard warnings from leaders in Europe and from Prime Minister Stephen Harper, who used a speech about his newly signed trade agreement with South Korea to repeat his call on Russian troops to vacate the Crimean Peninsula.
So far, Mr. Putin has shown little fear of international sanction.
In Kiev, a senior Ukrainian security official said Russia has amassed tens of thousands of troops near its border with Ukraine, and warned that the Ukrainian capital could be overrun in a matter of hours. Mr. Putin maintains that he is protecting the Russian-speaking majority in Crimea from a hostile parliament that forced a legitimately elected leader into exile. Mr. Obama, on Wednesday, flatly rejected that defence of Moscow's actions.
"We will continue to say to the Russian government, that if it continues with the path that it is on, that not only us, but the international community, the European Union and others, will be forced to apply a cost to Russia's violations of international law and its encroachments on Ukraine," Mr. Obama said.
The appearance of Mr. Obama and Mr. Yatsenyuk in front of television cameras at the White House capped a day during which Western powers sought to counter Mr. Putin's military intimidation with the diplomatic manoeuvring that presages international sanction.
U.S. Secretary of State John Kerry told lawmakers on Capitol Hill that he would meet his Russian counterpart, Sergei Lavrov, in London on Friday. Mr. Kerry declined to reveal what he intended to say to Mr. Lavrov, but warned that "it can get ugly fast if the wrong choices are made, and it can get ugly in multiple directions." Mr. Kerry added: "Our hope is there is a reasonable outcome here."
In Europe, German Chancellor Angela Merkel and Polish Prime Minister Donald Tusk said at a joint press conference that the European Union could sign an "association" agreement with Ukraine as early as next week, a move that would further pull the former Soviet republic out of Moscow's orbit.
Also on Wednesday, the Group of Seven economic powers – the U.S., Canada, Germany, Britain, France, Italy and Japan – issued a statement that said Russia would face sanctions unless it stopped everything it was doing to orchestrate a referendum on Crimea's future in Ukraine.
"All of the G7 countries remain collectively, strongly committed to the view that we will not accept Russia's illegal occupation of Crimea," Mr. Harper said during a speech to a business group in Vancouver.
Mr. Yatsenyuk's visit to Washington was more than show. He was expected to make a case of military and economic assistance. Neither he nor Mr. Obama discussed the details of their meeting.
"We want to be very clear that Ukraine is and will be part of the Western world, and our Russian partners have to realize that we are ready to make a new type, or craft a new type, of … relationship where Ukraine is part of the European Union, but Ukraine is a good friend and partner of Russia," Mr. Yatsenyuk said.
Nearly as intimidating as the presence of Russian troops is the economic turmoil Ukraine faces unless it soon gets a lifeline. The value of the country's currency has plunged some 20 per cent as investors flee for safety. The profligacy of Mr. Yanukovych and previous leaders has left Ukraine on the verge of a budget crisis.
Mr. Obama and the European Union both have promised help – in the case of the U.S., a $1-billion loan guarantee. But they want the International Monetary Fund to move first, setting the conditions that Ukraine will have to meet in return for financial aid. Mr. Yatsenyuk met Wednesday with Christine Lagarde, the IMF's managing director, but left empty-handed.
"We had productive discussion regarding policies needed to put Ukraine on the path of sound economic governance and sustainable growth, while protecting the vulnerable in society," Ms. Lagarde said in statement. "The IMF will continue to consult with its membership and other international financial institutions on how best to support the people of Ukraine."
With a report from Kathryn Blaze Carlson in Ottawa