When President Obama and Russian President Vladimir Putin got off the phone today, the White House said Moscow was in "clear violation" of international law with its actions in Crimea, but the Kremlin has a different view of the situation in Ukraine.
Putin today asked for and received authorization from the Duma - the Russian legislature - to use military force in Ukraine, and throughout the day armed men in unmarked uniforms patrolled airports in the Crimean cities of Simferopol and Sevastopol, the home of a Russian naval base.
The Russian president's request for authorization of military force said the move was necessary to protect Russian citizens, ethnic Russian Ukrainians and the troops stationed in Crimea:
"In connection with the extraordinary situation in Ukraine, the threat to the lives of citizens of the Russian Federation, our compatriots, and the personnel of the armed forces of the Russian Federation on Ukrainian territory (in the Autonomous Republic of Crimea)… I submit a proposal on using the armed forces of the Russian Federation on the territory of Ukraine until the normalization of the socio-political situation in the that country."
The official readout of Putin's conversation with Obama cited similar concerns:
The two presidents discussed in detail various aspects of the extraordinary situation in Ukraine.
In reply to Mr Obama's concern over the possibility of the use of Russian armed forces on the territory of Ukraine, Vladimir Putin drew his attention to the provocative and criminal actions on the part of ultranationalists who are in fact being supported by the current authorities in Kiev.
The Russian President spoke of a real threat to the lives and health of Russian citizens and the many compatriots who are currently on Ukrainian territory. Vladimir Putin stressed that in case of any further spread of violence to Eastern Ukraine and Crimea, Russia retains the right to protect its interests and the Russian-speaking population of those areas.
Ethnic Russians make up the largest segment of the population in both Eastern Ukraine and Crimea,