MOSCOW (AP) — Top diplomats from Russia, Ukraine, France and Germany discussed ways to advance the peace process for eastern Ukraine in Thursday's call, but failed to achieve any tangible progress.

The call follows a December summit in Paris where the leaders of the four nations agreed to make additional steps toward ending the fighting between Ukrainian forces and Russia-backed rebels. The six-year conflict that erupted after Russia's annexation of Ukraine's Crimea has killed more than 14,000 people.

Ukrainian Foreign Minister Dmytro Kuleba said at a briefing after the call the four ministers agreed that negotiators from Russia, Ukraine and the rebels should quickly discuss specifics of a new cease-fire. Numerous previous attempts to establish a lasting truce have failed amid mutual accusations.

Kuleba added that he called for speeding up efforts to ensure the release of remaining prisoners.

Russian Foreign Minister Sergey Lavrov told reporters that the Ukrainian authorities have continued to shun direct dialogue with the rebels, stymieing peace efforts. He emphasized that such negotiations are essential for implementing earlier agreements that envisaged a broad autonomy for the rebel regions.

Lavrov charged that Ukraine also has dragged its feet on selecting new areas for troop withdrawal from the line of contact.

Ukrainian President Volodymyr Zelenskiy, who was elected a year ago, has made settling the conflict in eastern Ukraine his top priority. Ukraine and the rebels have exchanged prisoners and withdrew their troops from several sections of the front line as part of confidence-building measures, but sporadic clashes have continued and efforts to negotiate a political settlement have stalled.

During their talks in December, the leaders of Russia, Ukraine, France and Germany scheduled their next meeting for April in Berlin, but the coronavirus pandemic scuttled those plans.