"The total advance of our units amounted to up two kilometres in depth along up to four kilometres of the front" in the direction of Lyman, the defence ministry said in a statement.

The army also said it took control of the village of Sergiivka as part of "successful counteractions".

Russia began a new assault along a northeastern stretch of the crescent-shaped frontline a few weeks after Ukraine began its own attacks further south in early June.

Moscow claimed on July 11 to have advanced 1.5 kilometres closer to Lyman -- a rail hub Ukraine reclaimed in October.

The Russians seem intent on forcing the Ukrainians to abandon their advance on captured cities such as Bakhmut and redeploy troops to defend the Lyman front.