The self-styled mayor of the eastern Ukrainian city of Slaviansk, which is controlled by armed pro-Russian separatists, said he had been in contact with mediators from the Organisation for Security and Cooperation in Europe (OSCE).
Vyacheslav Ponomaryov, speaking at a news conference in Slaviansk, did not say what he had discussed with the mediators.
Tensions remain high in eastern Ukraine after at least three died in a day of shooting during what was supposed to be an Easter truce.
In an exclusive interview with NBC News, the Ukrainian Prime Minister warns of the dangers of unchecked Russian expansion and aggression.
Russia, the US and the EU say that all sides have agreed to steps to "de-escalate" the crisis in Ukraine at talks in Geneva.