It's a routine they repeat frequently as Ukraine's army tries to battle through vast Russian minefields and heavily fortified trenches in the southern region of Zaporizhzhia. Kyiv says its troops are gradually pushing back Russian forces in the south after 18 months of occupation, but that fighting is heavy three months into the counteroffensive. "The Russians resist fiercely there (on the front line), they are trying to get back their positions," the mortar squad's commander, who uses the call-sign Hrai, told Reuters.