Meanwhile , Russia has begun an air defense drill 280 miles ( 450 kilometers ) from Ukraine 's border , reports Russian state-run news agency RIA Novosti . Putin to Ukraine : ' ` ` do not ignore the call for help '' Crimean lawmakers set a date for a referendum on staying in Ukraine or Crimea . Ukraine 's interim prime minister , U.S. President Obama call such a vote unlawful . West threatens Russia with punitive actions over Ukraine .
Putin to Ukraine : ' ` ` do not ignore the call for help '' Crimean lawmakers set a date for a referendum on staying in Ukraine or Crimea . Ukraine 's interim prime minister , U.S. President Obama call such a vote unlawful . West threatens Russia with punitive actions over Ukraine .