Ukraine’s President, Volodymyr Zelenskiy acknowledged for the first time that Ukrainian forces were fighting in the surprise offensive in Russia’s Kursk region.

Moscow’s forces were in their sixth day of intense battles against Kyiv’s largest incursion into Russian territory since the start of the war, which left southwestern parts of Russia vulnerable before reinforcement started arriving.

In a sign of the intensity of the Ukrainian invasion, Russia imposed a sweeping security regime in three border regions on Saturday, while Belarus, a staunch ally of Moscow, sent more troops to its border with Ukraine, accusing Kyiv of violating its air space.

In his nightly video address, Zelenskiy said he had discussed the operation with top Ukrainian commander Oleksandr Syrskyi, vowing to restore justice after Russia launched the full-scale invasion on its smaller neighbour in February 2022.

“Today, I received several reports from Commander-in-Chief Syrskyi regarding the front lines and our actions to push the war onto the aggressor’s territory,” Zelenskiy said on Saturday night, August 10.

“Ukraine is proving that it can indeed restore justice and ensure the necessary pressure on the aggressor.”

Russia’s defence ministry said on Sunday it had destroyed 14 Ukrainian drones and four Tochka-U tactical ballistic missiles overnight over the Kursk region, and 18 drones over other Russian regions that Ukraine

Russian President Vladimir Putin in a statement last week said the Ukrainian attack was a ‘major provocation.’

Russian military bloggers said the situation had stabilised after Russia’s reinforcements, though they said Ukraine was swiftly building up forces.

The bloggers say fighting is taking place as deep as 20 km (12 miles) inside the Kursk region, prompting some of them to question why Ukraine was able to pierce the Kursk region so easily.

Alexei Smirnov, Kursk’s acting governor, ordered local authorities to speed up the evacuation of civilians in areas at risk. On Saturday, Russia’s TASS state news agency reported that more than 76,000 people had been evacuated.

Russian Human Rights Commissioner Tatyana Moskalkova said she had sent an appeal to the United Nations demanding it condemn Ukraine’s actions in Kursk.

In a Telegram post, Moskalkova said she was asking the U.N. Human Rights commissioner to “take measures to prevent gross mass violations of human rights”.