"The militants fired 152mm and 122mm artillery on the positions of the Ukrainian armed forces for an hour. They also fired 82 mm and 120mm mortars," the report says.

"Between volleys of artillery, they used small arms and automatic mounted grenade launchers," said the press officer of the "M" sector (Mariupol area) of the front line, Yaroslav Chepurniy.

"In addition, Russian-backed militants attacked Ukrainian army positions 21 times in the area of Donetsk from Wednesday evening to Thursday morning. They fired heavy cannon artillery and tanks ten times on the Ukrainian troops there," the representative of "B" sector Yevhen Sylkin said.