President Barack Obama urged a diplomatic resolution for the Ukraine crisis to his Russian counterpart Vladimir Putin in a late night phone call, Thursday.

President Obama told Russian President Putin that deploying Russian forces in Ukraine's troubled autonomous Crimea region was a violation of Ukraine's sovereignty. This was the second phone conversation between the two leaders within a week.

The U.S. president also suggested that Russia send back forces to pre-existing Russian bases and support the upcoming elections in May in the troubled country.

"President Obama indicated that there is a way to resolve the situation diplomatically, which addresses the interests of Russia, the people of Ukraine, and the international community," the White House said in a statement, reports the USA Today.

In a statement issued Friday, Kremlin quoted President Putin as saying that Western leaders were dictating "absolutely illegitimate decisions to the eastern and south-eastern regions of Ukraine and Crimea," reports the Voice of America. "Russia cannot ignore calls for help and it acts accordingly, in full compliance with international law," President Putin said, Kremlin wrote in the statement.

Meanwhile, the Crimean parliament surprised the European Union leaders by voting in favor of holding a referendum on March 16 to decide on  joining Russia. Crimea, the autonomous republic of Ukraine, is dominated by ethnic Russian population.

However, Arseny Yatseniuk, the interim prime minister of Ukraine said that Crimea's decision to hold the referendum was "illegitimate" and that Crimea was and would remain an integral part of Ukraine. He added that the country's military was completely prepared to fight Russian troops' future incursions into their territory, reports France24.