OSCE Chairperson-in-Office and Serbian Foreign Minister Ivica Dacic has expressed alarm at the escalation of violence in the eastern part of Ukraine, Serbian mass media reported on Friday.

"I am deeply concerned about the escalation of the conflict in eastern Ukraine, particularly the use of heavy weapons, including unguided Grad rockets. All parties should respect the cease-fire and immediately stop using heavy weapons in civilian areas," Dacic said in a statement

"An immediate meeting of all signatories of the Minsk Documents should now be held and each party must pledge to ensure full respect and implementation of the provisions contained in those documents," he said.