U.S. officials confirm influx of Russian troops into Crimea - The Washington Post: U.S. officials said Friday that Russian troops had entered Crimea, as President Obama warned that there “will be costs for any military intervention” and vowed to stand by the Ukrainian people.
Obama said he was “deeply concerned by reports of military movements,” that “would represent a profound interference in matters that must be determined by the Ukrainian people” and would constitute a “clear violation” of international law.