Russian President Vladimir Putin and his Ukrainian counterpart Petro Poroshenko agreed to work on implementing a cease-fire between pro-Moscow separatists and Ukrainian authorities, French presidency office said Monday.

A communique issued by the Elysee followed a long telephone conversation between Putin, Poroshenk, French President Francois Hollande and German Chancellor Angela Merkel. They vowed to set " an effective mechanism" to reinforce border controls.

They also agreed to work on the release of more hostages and prisoners and the organization of substantial tripartite negotiations, according to the statement.

Top diplomats of Russia and Ukraine were scheduled to meet later in the day, it added.

The insurgency in the largely Russian-speaking east of Ukraine erupted in April after street protests in Kiev toppled former leader Viktor Yanukovich.

On June 20, Poroshenko announced a unilateral ceasefire plan aiming at peacefully resolving the conflict in eastern regions, calling on the rebels to lay down weapons and start peace talks with the government in Kiev.