Ukraine has launched a new offensive in the Kursk region of Russia, the Russian Ministry of Defense announced.
In a statement, the military said efforts to destroy Ukrainian attack groups were continuing. Officials in Ukraine also suggest an operation is underway.
Ukraine first launched its invasion of Russia's Kursk region in August last year, seizing a large swath of territory.
In recent months, Russian forces have made great strides in the area, pushing the Ukrainians back, but failing to drive them out completely.
In a statement published on Telegram on Sunday, the Russian Ministry of Defense said: “Around 9 a.m. Moscow time, in order to stop the advance of Russian troops in the direction of Kursk, the enemy launched a counterattack by an assault squad consisting of two tanks, one anti-obstacle vehicle and 12 armored fighting vehicles'.
The head of Ukraine's presidential office, Andriy Yermak, said “there is good news from the Kursk region” and that Russia “is getting what it deserves.”
Ukraine's top anti-disinformation official Andriy Kovalenko said in a Telegram publication on Sunday: “The Russians at Kursk are in great alarm because they have been attacked from several directions and this has been a surprise to them.”
It is unclear whether the offensive is large enough to bring about significant changes on the front line.
Kiev's forces have reportedly been short of manpower and have been losing ground in eastern Ukraine in recent months as Russian troops advance.
It comes after the Ukrainian Air Force reported that Russia carried out another drone strike against Ukraine overnight.
He said he shot down 61 drones over Kyiv, Poltava, Sumy, Kharkiv, Chernihiv, Cherkasy, Dnipropetrovsk, Zhytomyr and Khmelnytskyi regions
There were no direct hits, but several houses were damaged in the Kharkiv region by an intercepted drone, the air force said.
In November, Ukraine reported that its troops were involved in a battle with North Korean troops in the Kursk region.
The appearance of North Korean troops was in response to a surprise attack launched across the border by Ukrainian troops in August, advancing 18 miles (30 km) into Russian territory.
Moscow evacuated almost 200,000 people from areas along the border, and President Vladimir Putin condemned the Ukrainian offensive as a “major provocation”.
After two weeks, Ukraine's supreme commander claimed control of more than 1,200 sq. km of Russian territory and 93 villages.
Some of this territory has been returned by Russia, but Ukraine still has troops in the Kursk region.