The French Presidency says France, Germany, and Russia back plans for a complete cease-fire in eastern Ukraine from next week.
Fighting between Ukrainian forces and Russian-backed separatists has killed more than 6,400 people since March 2014.
A cease-fire agreement reached in Minsk in February has been regularly violated.
But on August 26, representatives from Kyiv and the rebels agreed to strive for an end to all truce violations from September 1 -- the day the new school year is to begin.
After the leaders of France, Germany, and Russia spoke by telephone on August 29, French President Francois Hollande's office said the three “strongly backed” the call for a complete truce from September 1.
It said Hollande also agreed with German Chancellor Angela Merkel and Russian President Vladimir Putin that it would be useful to hold a summit with Ukraine's Petro Poroshenko “in the coming weeks.”
According to the Kremlin, Putin expressed his concern over the "continual bombardment of towns” by the Ukrainian Army and “the concentration of Ukrainian armed forces all along the demarcation line."
Putin also insisted on a direct dialogue between Kyiv and separatist leaders and the removal of economic blockades on the region.
A German statement said the Western leaders voiced concerns about plans by the separatists to hold elections outside the framework of Ukrainian law.
On August 28, U.S. Vice President Joe Biden spoke to Poroshenko by phone.
The White House said Biden "strongly criticized statements by separatist leaders indicating their intention to take additional territory and hold local elections outside of the Ukrainian legal framework, in direct contravention of the Minsk agreements."
Biden also offered U.S. support for constitutional amendments Poroshenko has proposed to decentralize power and hold local elections while maintaining a unitary federal government in Kyiv.
With reporting by Reuters and AFP