BRUSSELS (Reuters) - European Council President Donald Tusk, the chairman of EU leaders' meetings, called on Russia on Thursday to use its influence with rebels in east Ukraine to stop a recent spike in violence there.


"We are reminded again of the continued challenge posed by Russia's aggression in eastern Ukraine," Tusk told a news conference. "The fighting must stop immediately. The ceasefire must be honored."


"Russia should use its influence to disengage the Russian-backed separatists."


The latest spike in violence in east Ukraine - where Russia-backed rebels face off against Kiev government troops - coincides with the taking office by the new U.S. President Donald Trump, who has promised to seek rapprochement with Moscow.


The Kremlin has said the latest flare-up of hostilities in eastern Ukraine shows the need for a swift resumption in dialogue between the United States and Russia.


(Reporting by Gabriela Baczynska)