President Obama addressed the "fluid" situation in Ukraine in a
brief statement to the press this evening.
“We are now deeply concerned by reports of military movements taken by the Russian Federation inside of Ukraine,” Obama said, speaking at the White House. “Any violation of Ukraine’s sovereignty and territorial integrity would be deeply destabilizing.”
Obama also stated that the United States would stand with the international community "in affirming there will be costs from any violation," but did not elaborate on what those costs would be.
3:20 PM PT: A transcript of Obama's remarks can be found here.