French President Francois Hollande voiced his "concern" over a spike in tensions in Ukraine, in a telephone call with Russian leader Vladimir Putin, his office said Tuesday.
"The president ... expressed his concern over a rise in tensions these past weeks and a growing number of ceasefire violations," it said in a statement after the call, which also included German Chancellor Angela Merkel
"He underlined the risk an escalation of violence posed to the (peace) process."
Ukraine has been in the grip of a conflict between its army and pro-Russian separatists in the east of the country for two years.
Kiev and the West accuse Russia of supporting the separatist rebels in eastern Ukraine and deploying troops across the border -- claims Moscow denies.
More than 9,500 people have been killed since the conflict started in April 2014, and deadly clashes continue to occur despite several truces.
Tensions between Russia and Ukraine soared last week after Putin accused Kiev of attempting an armed incursion into Crimea -- the Black Sea peninsula annexed by Moscow in 2014.
Meanwhile as fighting increased in the east, Ukraine's President Petro Poroshenko warned of a possible "full-scale" Russian invasion.