Russian forces tried to advance again from north of Sloviansk but their offensive was unsuccessful and they withdrew, the Ukrainian military said.
The battle occurred near Mazanivka on the border of the Donetsk and Kharkiv regions, an area that first saw Russian efforts to break through more than 40 days ago, according to the General Staff.
Another Russian assault further east also failed, despite support from combat aircraft, it added. "Near Ivano-Dariivka, with the support of aviation, the enemy conducted unsuccessful assault actions. It suffered losses and withdrew," the General Staff said.
Fighting has been going on in that district for well over a month.
Ukrainians say Russian objectives remain the same — they are "focused on conducting active offensive and assault actions in the Kramatorsk, Bakhmut, and Avdiivka directions," the General Staff said.
Bakhmut and Avdiivka have been within a few miles of the front lines for several months, but they remain in Ukrainian hands.
The Ukrainians say further efforts to advance in the Bakhmut area had been rebuffed.
"Offensive and assault actions of the occupiers in the Soledar, Zaitseve and Maiorsk districts ended with losses and withdrawal," it added, saying another attack just south of Bakhmut [in the Vershyna area] had also been foiled.
Meanwhile, the Russians appear to have put renewed effort into breaking through Ukrainian lines in southern Donetsk, between Pavlivka and Novomykhailivka, where "hostilities continue," according to the General Staff.
Further north, in the Kharkiv region, the Ukrainian General Staff said nearly 20 settlements had come under fire, including several close to the border with Russia.
The mayor of Kharkiv, Ihor Terekov, urged civilians to stay indoors after shells landed in the Saltivka district.