Western leaders warned Russia to cease its attempts to annex the Crimea or otherwise face sanctions.
U.S. President Barack Obama, said Moscow would pay a price if it continues its current path.
Speaking from the White House after meeting with interim Prime Minister of Ukraine Arseniy Yatsenyuk, Obama said a referendum, scheduled for Sunday, on the annexation of Crimea into Russia, is a violation of international law.

Earlier, the European Union and the G-7, said they would take action against Russia if the referendum takes place.