WASHINGTON — President Barack Obama declared that the U.S. would "completely reject" a vote opening the door for the strategic Ukrainian peninsula to join Russia if the election goes ahead on Sunday.
Adding pressure on Russia, the Senate advanced a package on Wednesday of potentially tough economic sanctions against Moscow.
Obama made a point of welcoming Ukraine's new leader to the White House, declaring as they sat side-by-side that he hoped there would be a "rethinking" by President Vladimir Putin of the referendum. Obama derided the vote as a "slap-dash referendum" and warned that if it occurs, the international community "will be forced to apply a cost to Russia's violation of international law."
Secretary of State John Kerry also was talking tough, telling Congress, "It can get ugly fast if the wrong choices are made, and it can get ugly in multiple directions." Kerry will meet with Russian Foreign Minister Sergei Lavrov on Friday in London in a last-ditch effort to halt the referendum.
Amid the maneuvering, Obama met in the Oval Office with new Prime Minister Arseny Yatsenyuk, praising him and the Ukrainian people as the two sat for television coverage. The meeting was aimed at showcasing the U.S.' commitment to Ukraine, the former Soviet republic at the center of rising tensions between East and West.
"There is another path available and we hope President Putin is willing to seize that path," Obama said. "But if he does not, I am very confident that the international community will stand firmly behind the Ukrainian government."
Yatsenyuk, a 39-year-old pro-Western official who speaks fluent English, defiantly declared that his country "will never surrender" in its fight to protect its territory.
He arrived in Washington seeking financial help to stabilize his fledgling government. The Senate bill that advanced out of committee on Wednesday would authorize $1 billion in loan guarantees.
The measure, which next would go to the full Senate, also would allow the Obama administration to impose economic penalties on Russian officials responsible for the intervention in Crimea or culpable of gross corruption.
Ukraine's pro-Russian President Viktor Yanukovych, fled Kiev for Russia in late February amid growing protests over his decision to scrap an agreement to boost ties with Europe.
Shortly after Yanukovych left, Russia began moving military forces into Crimea, a strategically important peninsula where 60 percent of the population is ethnic Russian.
Speaking to reporters following the meeting Wednesday, Yatsenyuk cast Putin's move into Crimea as part of a broader plan to reassert Russian influence in Ukraine.
"The idea is not just to annex Crimea, but to invade central Ukraine, the Ukrainian capital and to start a war," said Yatsenyuk, who plans to address the United Nations on Thursday.
Putin has so far rebuffed efforts by the U.S. to punish Russia for its military maneuvers in Ukraine. The U.S. has put in place travel bans for Russian and Ukrainian officials involved in the Crimea advances.