US President Barack Obama has urged his Russian counterpart Vladimir Putin to withdraw troops from near the Ukraine border, in the first direct contact between the leaders since the takeover of Crimea.
The White House said on Saturday that Obama had urged Putin in a "frank and direct" telephone conversation to ease tensions by removing troops, and respond to proposals for a diplomatic solution put forward by the US earlier this week.
The Kremlin, however, said that Putin had used the conversation to warn Obama that the interim government of Ukraine was allowing a "rampage of extremists" and suggested "possible steps by the international community to help stabilise the situation".
The Friday telephone conversation is believed to have been the first between Obama and Putin since the US and the EU began imposing sanctions on Russia over the takeover of the peninsula.
The Russian president has recently ordered troops to assemble by the border with Ukraine, with the US estimating on Friday, that his total forces in Crimea numbered about 40,000.
Obama had earlier told CBS news that Russian troops were "massing along that border under the guise of military exercises".
He insisted that Russia needed "to move back those troops and to begin negotiations directly with the Ukrainian government, as well as the international community".
He denied Russian statements that the West was trying to encircle Russia.
"We have no interest in circling Russia and we have no interest in Ukraine beyond letting Ukrainian people make their own decisions about their own lives," he said.
Russian Defence Minister Sergei Shoigu, meanwhile told the Interfax news agency that his country was completely in control of Crimea and that all Ukrainian soldiers had left.
Putin also congratulated the Russian armed forces. "The recent events in Crimea were a serious test. They demonstrated the new capacities of our armed forces in terms of quality and the high moral spirit of the personnel," he said, quoted by Russian news agencies.