German Chancellor Angela Merkel, French President Francois Hollande and Ukrainian President Petro Poroshenko demanded Sunday “an immediate ceasefire” in war-torn eastern Ukraine, where truce talks have failed and deadly fighting has worsened by the day, Agence France-Presse reported.

The three leaders also said they were disappointed in “the failure of the talks” Saturday in Minsk, the capital of Belarus where negotiations are being held, AFP said. Top Ukrainian, Russian and European envoys had opened a new round of talks, hoping to end the two-week surge in violence between Ukrainian troops and pro-Russian rebels, the New York Times reported.

Plans to begin negotiations Friday buckled when Russian-backed rebel leaders did not show up. Denis Pushilin, a negotiator for the separatists, said Saturday the self-proclaimed republic leaders in rebel-held Donetsk and Luhansk would not participate in ceasefire talks unless Ukraine declared a truce first. “Firing by Ukrainian government troops has to stop, because our leaders are fully involved in repelling attacks,” Pushilin told the New York Times.

However, former Ukrainian President Leonid Kuchma, who has engaged in the negotiations, said the Russian separatists must abide by the previously agreed upon truce rather than impose new demands. “The Ukrainian side does not accept any ultimatums or preliminary conditions,” Kuchma said in a statement Saturday, the Times reported.

Representatives of Ukraine, Russia and rebel groups signed the Minsk Protocol in September to stop fighting in the Donbass region of Ukraine, but more than 1,000 people have been killed in fighting since then. The nine-month international conflict has killed more than 5,000 people. U.S.-Russian relations are at their worst since the Cold War years, the United Nations said.

“We must find a way to stop it and must do so now,” Jeffrey Feltman, the U.N. Undersecretary-General for Political Affairs, said last week while calling for a revival of the Minsk deal.