People hold plackards reading "Crimea is Ukraine" during a rally at the Independence square in central Kiev on March 1, 2014. Pro-Russian forces tightened their grip on Crimea on Saturday as the Kremlin vowed to help restore calm on the restive Ukrainian peninsula and Washington warned of "costs" to Moscow should it order in troops. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'Crimea is Ukraine' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

A man holds a placard reading 'Crimea is Ukraine' (C) as he takes part to a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'I pray for Crimea #Ukraine' and 'Crimea we love you' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'I pray for Crimea #Ukraine' and 'Crimea we love you' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'I pray for Crimea #Ukraine' and 'Crimea we love you' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'Crimea is Ukraine' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'Crimea is Ukraine' and a map of Ukraine during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

People hold placards reading 'Crimea is Ukraine' and 'I pray for Crimea' during a rally on Independence square in central Kiev on March 1, 2014. Ukraine accused Russia on March 1, 2014 of sending thousands of extra troops into Crimea as the Kremlin vowed to help restore calm on the flashpoint peninsula and Washington warned of "costs" to Moscow should it use force. AFP PHOTO / LOUISA GOULIAMAKI

A woman holds a sign during a demonstration in front of the Russian Embassy in Kiev on March 1, 2014. Russian President Vladimir Putin on March 1, 2014 submitted a request to the upper house of parliament asking approval for the use of Russian troops in Ukraine, the Kremlin said. "In connection with the extraordinary situation in Ukraine and the threat to the lives of Russian citizens... I submit to the Federation Council a request to use the armed forces of the Russian Federation on Ukrainian territory until the normalisation of the political situation in that country," the Kremlin quoted Putin as saying in the document. AFP PHOTO/ YURY KIRNICHNY

A demonstrator holds a sign reading "Putin get out of Ukraine" during a demonstration in front of the Russian Embassy in Kiev on March 1, 2014. Russian President Vladimir Putin on March 1, 2014 submitted a request to the upper house of parliament asking approval for the use of Russian troops in Ukraine, the Kremlin said. "In connection with the extraordinary situation in Ukraine and the threat to the lives of Russian citizens... I submit to the Federation Council a request to use the armed forces of the Russian Federation on Ukrainian territory until the normalisation of the political situation in that country," the Kremlin quoted Putin as saying in the document. AFP PHOTO/ YURY KIRNICHNY

A demonstrator holds a sign reading "Crimea is Ukraine" during a demonstration in front of the Russian Embassy in Kiev on March 1, 2014. Russian President Vladimir Putin on March 1, 2014 submitted a request to the upper house of parliament asking approval for the use of Russian troops in Ukraine, the Kremlin said. "In connection with the extraordinary situation in Ukraine and the threat to the lives of Russian citizens... I submit to the Federation Council a request to use the armed forces of the Russian Federation on Ukrainian territory until the normalisation of the political situation in that country," the Kremlin quoted Putin as saying in the document. AFP PHOTO/ YURY KIRNICHNY