The Russian army acknowledged that Ukrainian forces had penetrated its territory by up to 30km in some places.
Moscow on Sunday acknowledged Ukrainian troops had pierced deep into the Kursk border region in an offensive that a top official in Ukraine said aimed to “destabilise” Russia and “stretch” its forces.
Later Sunday, each country blamed the other for a fire at the Zaporizhzhia nuclear plant in southern Ukraine occupied by Russian forces, though both sides – and the UN nuclear watchdog – said there was no sign of a nuclear leak.
Kyiv has deployed thousands of troops to the surprise operation, a Ukrainian security official said, seizing the battlefield initiative after months of slow Russian advances across the east.
“The aim is to stretch the positions of the enemy, to inflict maximum losses and to destabilise the situation in Russia as they are unable to protect their own border,” the security official said on condition of anonymity.
The assault appeared to catch the Kremlin off guard, with Moscow’s army rushing in reserve troops, tanks, aviation, artillery and drones in a bid to quash it.
But the army on Sunday appeared to concede that Ukraine had been able to penetrate its territory by up to 30km (20 miles) in places.
In a daily briefing on the situation in the western Kursk region, the defence ministry said it had “foiled attempts” by Ukraine’s forces to “break through deep into Russian territory” using armoured vehicles.
But it said some of those forces were near the villages of Tolpino and Obshchy Kolodez, some 25km and 30km from the Russia-Ukraine border.
The Ukrainian official also said Russian claims that Kyiv had deployed 1,000 troops were a serious underestimate.
