President Obama asked Russian President Vladimir Putin to use his influence to promote greater peace and stability in eastern Ukraine and to make an effort to work with a new Ukrainian government that Obama said is "willing to go the extra mile."
In a Monday telephone call, Obama told Putin that Moscow would face "additional costs" if the world didn't see concrete actions to de-escalate the situation, White House Press Secretary Josh Earnest said.
Ukrainian President Petro Poroshenko is trying to "resolve the situation and to restore some peace and security to the entire country that he governs," Earnest said. "What we need is some cooperation with President Putin and the Russians to make that a reality."
The phone call came to light after the Kremlin announced it. According to the official Russian account, reported by Reuters news agency, Putin said that, in order to normalize the situation in eastern Ukraine, it was necessary to "effectively end fighting and start direct talks between the conflicting parties."
Putin has said that Poroshenko's declared cease-fire in the east will work only if the Ukrainian government agrees to talk with the insurgents fighting over the border regions.
In the call, Obama asked Putin to support a peaceful outcome instead of "allowing the provision of arms and materiel across the border and continuing support for militants and separatists who are further destabilizing the situation in Ukraine," Earnest said.
"Though we believe a diplomatic solution is still possible," Earnest said, "Russia will face additional costs if we do not see concrete actions to de-escalate the situation."