The United States is hopeful that after months of attacks and tensions "significant progress" could be made this week to end the fighting in eastern Ukraine, a US official said.
Washington had been "encouraged" by the talks, between Russian President Vladimir Putin and the incoming Ukrainian leader Petro Poroshenko, in Normandy last week, State Department deputy spokeswoman Marie Harf said.
She also welcomed the participation of the Russian ambassador to Kiev at Poroshenko's inauguration.
Putin on Saturday ordered the Russian border guards to reinforce the state frontier with Ukraine and take all necessary measures to prevent illegal crossings of armed convoys, a move which was also welcomed by the US administration.
"I think now we're calling on Russia to follow up its words with actions," Harf told reporters.
"There's a path forward here, we've always said there was, for de-escalation."
She added that President Putin had "called on the separatists" to stop the attacks in eastern Ukraine and "I think we could see significant progress."
US Secretary of State John Kerry today said that while "there is a great deal of work ahead, the path forward President Poroshenko has proposed would lead to a de-escalation of tensions."
"Ukraine can be a bridge between Russia and the west marked by strong economic relationships with both sides," he added.
