The Russian Defense Ministry claimed its forces have captured Ukrainian positions and observation points around the village of Vilshana, north-east of Kupyansk in Kharkiv region.
It said that assault groups of the 6th Combined Arms Army defeated up to a platoon of infantry in the area (between 20-50 soldiers), where Russian forces have been trying to take ground for several weeks.
The Defense Ministry said Ukrainian counterattacks had been rebuffed.
It also claimed that a Ukrainian attack further south, in Novoselivske, had been thwarted and that Ukrainian mortar positions and other equipment had been destroyed.
CNN is unable to confirm the majority of battlefield reports from either side.
A contested region: Kupyansk was captured by Russia in the early stages of its invasion but was liberated last September.
In July a Ukrainian official said Russia had amassed tens of thousands of troops and hundreds of tanks in the area.