UPDATED 5:39 EST
The Ukrainian ambassador to the U.N. claims there are 15,000 new Russian troops in Crimea.
According to the Guardian, Russian President Vladimir Putin and U.S. President Barack Obama spoke for 90 minutes on the phone starting around 4 p.m. EST. The two reiterated their stances. Obama requested that Putin draw Russian forces back to bases while Putin reminded Obama that he saw "real threats to the life and health of Russian citizens and compatriots on Ukrainian territory."
2:29 EST: Ukraine's acting President Oleksandr Turchnyov has ordered the Ukrainian army to be put on "combat alert." The Ukranian Prime Minister has said Russian forces must return to their bases and further Russian aggression will result in war.
Russian President Vladimir Putin now has the approval of Russia's upper house of Parliament to forcefully deploy troops in Crimea and to recall Russia's ambassador to the U.S.
As of 1 p.m. EST, President Putin has not decided whether or not he will exercise either of those measures.
He wrote a letter to the upper house (Federation Council) earlier today requesting the authority to use the Russian military in Crimea "pending normalization of the public and political situation in that country." The letter called the situation in Ukraine "extraordinary" and cited a threat to Russian citizens, military personnel and "compatriots" as reason for force.
The Federation Council unanimously supported Putin in a 90-0 vote. They requested Putin withdraw Russia's ambassador to the U.S. over President Obama's comments on the issue.
President Barack Obama announced earlier that the U.S. "will stand with the international community in affirming that there will be costs for any military intervention in Ukraine."
The Federation Council had earlier asked Putin to take "exhaustive measures" to protect Russians in Crimea and to help Russia's "brotherly Ukrainian people achieve stabilization and channel the current crisis into a civilized legal track ..."