The White House has declared a freeze on assets of 11 Russian officials linked to the political push for Crimea's independence from Ukraine and possible annexation by Russia.
The Obama administration announced the sanctions Monday following the European Union, which designated 21 officials from Russia and Ukraine for travel bans and trade sanctions.
The moves came in response to Crimea's declaration of independence from Ukraine Monday and it plans to apply to become part of Russia. Crimea's regional assembly declared independence for the region after a referendum on Sunday indicated voters' overwhelming support for joining the Russian Federation.
In addition to responses from the U.S. and the European Union, NATO released a statement Monday calling the vote "illegal and illegitimate." It said the vote violates the Ukrainian constitution and international law, and added that the circumstances under which the referendum was held were "deeply flawed and therefore unacceptable."
Despite objections from the international community, a delegation of Crimean lawmakers is traveling to Moscow Monday to discuss additional procedures required to become part of the Russian Federation.
Ukraine's parliament has approved a partial mobilization of reservists in response to the crisis.