Ammon News - AMMONNEWS - In several calls made to key his European allies, U.S. President Barack Obama expressed “grave concern” on Saturday over Russia’s actions in Ukraine.

Obama made calls to French counterpart Francois Hollande, British Prime Minister David Cameron and Italian leader Matteo Renzi.

The remarks came as Washington warned further military escalation could jeopardize chances of brokering a diplomatic solution to the crisis.

“The leaders reiterated their grave concern over Russia’s clear violation of international law and reaffirmed their support for Ukraine’s sovereignty and territorial integrity,” a White House summary of the calls said, according to Agence France-Presse.

Meanwhile, 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.

*Agencies