Washington: President Barack Obama held telephone talks with key European allies on Saturday amid warnings of "new measures" against Russia over the crisis in Ukraine.
The White House confirmed that Obama discussed Ukraine in calls with French counterpart Francois Hollande, British Prime Minister David Cameron and Italian leader Matteo Renzi.
Obama also hosted a conference call with the leaders of Lithuania, Latvia and Estonia to discuss the ongoing situation.
Details of the calls were not immediately available but the French presidency said in Paris that Hollande and Obama discussed "new measures" against Russia if it failed to act to defuse the crisis.
Hollande and Obama insisted on the "need for Russia to withdraw forces sent to Crimea since the end of February and to do everything to allow the deployment of international observers," Hollande`s office said.
"If there`s a lack of progress in this direction, new measures will be taken which would noticeably affect relations between the international community and Russia, which is in no-one`s interest."
Unrest in Ukraine, which resulted in the ouster last month of pro-Russian president Viktor Yanukovych, has worsened since the Crimean parliament`s decision Thursday to secede and stage a March 16 referendum on joining Russia.
Ukraine also said there were now 30,000 Russian soldiers in Crimea -- 5,000 more than the contingent allowed under an existing agreement with Kiev.
Russia says it has stepped up protection of its naval base on the peninsula and is working together with local self-defense units but refuses to acknowledge deploying extra troops.