Russian troops have managed to advance 2 km (1.24 miles) to the west in four days along the frontline in Ukraine, the Interfax news agency reported on Monday, citing a statement by the Russian Defence Ministry.

"The Russian servicemen broke the enemy's resistance and advanced several kilometres deeper into its echeloned defence," the agency cited the report. "In four days the front moved 2 kilometres to the west."

There were no details which part of the large frontline, encompassing several Ukrainian regions in the country's south and east, has moved.

Reuters was not able to independently verify the battlefield reports.

Some of the fiercest fighting in recent months has taken place in the Donetsk region in southeastern Ukraine that is partially occupied by Russia and which Moscow wants to occupy fully.

Valeriy Zaluzhnyi, commander-in-chief of Ukraine's Armed Forces, said on Saturday that Ukraine's troops hold defence along the frontline in Donetsk and in some areas have managed to regain previously lost positions.