The Ukrainian military says Russian units are being reinforced on the approaches to Sloviansk as they prepare to resume an offensive toward the eastern city.
Neighboring Kramatorsk is the largest urban area in Donetsk still under Ukrainian control.
The General Staff said Friday the Russians are concentrating a force of up to 20 battalion tactical groups in the area. The Russians had tried to launch an attack on two towns north and northwest of Sloviansk — Barvinkove and Sviatohirsk — but had been unsuccessful, the General Staff said.
It's unclear whether the Russians have taken further territory to the east of Sloviansk after winning control of the town of Lyman late last month. The Ukrainian side says Russian forces have used artillery in two areas closer to Sloviansk — Shchurove and Brusivka.
In Severodonetsk, the General Staff said battles continue: "Under cover of artillery fire, the [Russians] stormed residential areas in the eastern part of the city. [The enemy] has partial success."
But the Russians had made no headway in their efforts to advance on other settlements in the pocket of territory that Ukrainian forces continue to defend — that includes Bakhmut, Soledar and Lysychansk. Once again, the General Staff said, the Russians had tried to cross the Siverskiy Donets River and "to create conditions for its crossing by the main forces of the force."
The river has proven to be a major barrier to Russian forces.
Fighting has picked up north of Kharkiv, where Ukrainian forces have regained territory in recent weeks. The General Staff reported that Russian forces were trying to "restrain the advance of our troops in the direction of the State Border. [The enemy] continued to fire on units of the Defense Forces using aircraft, artillery, multiple rocket launchers, mortars and tanks."
Russian action included an airstrike by Mi-8 helicopters at the positions of Ukrainian troops in the areas of the settlements of Slatyne and Dementiivka, rural settlements north of Kharkiv.