"Over the last day Russian-terrorist forces attacked Ukrainian positions nearly 20 times," the head of the Information Resistance Center for Military and Political Studies, Dmytro Tymchuk, wrote on Facebook on Monday.

Since the September 5 ceasefire, which was declared under the Minsk Protocol agreement, Russian forces and pro-Russian militants had by September 20 violated the truce more than 2,150 times, Tymchuk said.

"In particular, Ukrainian troops were attacked seven times with mortars and small arms near Nikishyno,” he said.

“There have [recently] been small arms attacks on the checkpoints of the anti-terrorist operation forces near Lomakino, Chernukhino, Bohdanivka, Hranitne, Novolaspa, Avdiivka and the airport of Donetsk," he said.