Germany and France are "extremely concerned" about the situation in eastern Ukraine, especially along the line of contact between pro-Russian separatists and government forces, the two countries' leaders said on Thursday.
German Chancellor Angela Merkel and French President Francois Hollande spoke ahead of an expected meeting next week with Russian President Vladimir Putin.
In a joint statement, Merkel and Hollande strongly endorsed a cease-fire deal to take effect at the start of the new school year that was brokered by the trilateral contact group of Germany, France and Poland.
They said the accord should lead to a lasting stop to the fighting that began in 2014.
Merkel, Hollande and Putin agreed earlier to meet to discuss the situation in Ukraine on September 4-5 in China on the sidelines of the G-20 summit, the Kremlin said last week.
A recent surge in fighting in eastern Ukraine and fresh tensions in Crimea, the Ukrainian region annexed by Russia in 2014, have raised concern that a much violated truce agreed in Minsk in February 2015 could collapse irretrievably.
The 12-point Minsk peace deal was engineered by Ukraine, Russia, Germany and France. Its aim was to end a conflict that the U.N. rights office said on Wednesday had killed more than 9,550 people, including soldiers, civilians and members of armed groups, since April 2014.
Conditions including a complete cessation of fighting, a pullback of heavy weapons from front lines and release of prisoners of war have not yet been fulfilled, raising concerns the Minsk truce pact will not survive.