"Militants have simultaneously used 120mm and 82mm mortars to fire on the town's industrial area, cynically ignoring the Minsk agreements again," the ATO HQ wrote on Facebook on Sunday.
What is more, illegally armed groups repeatedly used automatic grenade launchers and small arms to shell ATO forces near Avdiyivka and the village of Mayorsk, which were also under sniper fire, it said.
"During the day the intensity of militant fire remained at yesterday's level, as six attacks have been reported," the ATO said, citing reports as of 18:00 local time on Sunday.
The situation along the contact line remains tense.
"Since the very morning terrorists had been active in the Mariupol sector. They first used small arms and large-caliber machine guns to shell ATO positions near the village of Troyitske, and then they attacked Ukrainian troops near the villages of Hranitne and Mayorsk," it said.
What is more, the enemy continued using heavy weapons in the sector, in particular, 120mm mortars.
"Ten enemy bombs exploded near the village of Shyrokyne [close to the Ukrainian-controlled strategic port city of Mariupol] within a few minutes," he added.