Obama asks separatist to lay down weapons

The U.S. President Barack Obama told his Russian counterpart, Vladimir Putin, he is "very concerned" about the actions of Russia in Ukraine and urged the pro-Russian separatist militias to lay down their arms, during a telephone conversation held on Monday.

"The president expressed deep concern over the support the Russian government gave to the armed separatist actions that threaten to undermine and destabilize the Government of Ukraine," the White House announced in a statement.

Obama also stressed the need for "all irregular forces (armed) present in the country to lay down their arms" and urged Putin to "make use of its influence over the pro-Russian groups to convince them to leave the buildings they occupy" in Ukraine and "lay down their arms," said a White House press release.

During this telephone conversation, which took place at Moscow's request, the U.S. president has signaled that despite the "rhetoric" of the Russian authorities, "the Government of Ukraine showed a remarkable restraint."

Finally, Obama said that "increasing the political and economical isolation of Russia is the result of its actions in Ukraine and stressed that Russia will pay certainly more if it continues" this way.