Key NATO leaders agreed during a summit meeting on Thursday that Russia should faced increased sanctions for its actions in eastern Ukraine, the White House said.

U.S. President Barack Obama, British Prime Minister David Cameron, French President Francois Hollande, German Chancellor Angela Merkel and Italian Prime Minister Matteo Renzi sat down with Ukraine President Petro Poroshenko on the fringes of a NATO summit in Wales.

"The leaders reiterated their condemnation of Russia's continued flagrant vioaltion of Ukraine's sovereignty and territorial integrity, and agreed on the need for Russia to face increased costs for its actions," a White House statement said.

Hollande told reporters a decision on further European Union sanctions, to be taken in Brussels on Friday, would depend on events in the next few hours, as efforts continue to agree a ceasefire between Kiev and Russian-backed separatists.