At least 13 people have been injured in the city of Kursk after debris from a destroyed Ukraine-launched missile fell onto a nine-storey residential building, officials of the Russian border Kursk region say.

Moscow’s forces are in their sixth day of intense battles against Kyiv’s largest incursion into Russian territory since Russia launched a full-scale invasion on its smaller neighbour last week, with local authorities rushing to evacuate areas at risk.

Alexei Smirnov, Kursk’s acting governor, said in a post on the Telegram messaging app on Sunday that two of the injured were in serious condition.

Residents of the building were to be evacuated to a temporary accommodations centres, Kursk Mayor Igor Kutsak said on Telegram. He added that the whole city was under air raid alerts.

Kutsak posted a photo of a residential building with blown out windows and damaged balconies and facade of a residential building at night.

Reuters could not independently verify the reports from Kursk. There was no immediate comment from Ukraine.

Moscow has announced a “counter-terrorism operation” to increase security in the border region where an incursion this week by Ukrainian forces caught Russian troops off-guard and exposed military vulnerabilities https://t.co/gir6npbeLX

— breakingnews.ie (@breakingnewsie) August 10, 2024

Earlier Ukraine President Volodymyr Zelensky acknowledged for the first time that Ukrainian forces were fighting in Russia’s Kursk region and said the operation was part of Kyiv’s drive to restore justice after Russia’s 2022 invasion.

Russia said Ukrainian forces pushed into Kursk region on Tuesday and Russian military bloggers have acknowledged they made some headway, while saying the situation had since stabilised.

Zelensky had previously stayed silent about the operation.

In his nightly video address on Saturday, the president said he had discussed the operation with top Ukrainian commander Oleksandr Syrskyi, while not forgetting the battles troops face on the difficult eastern front.

“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,” he said.

“I am grateful to every unit of the defence forces for ensuring that. Ukraine is proving that it can indeed restore justice and ensure the necessary pressure on the aggressor.”

Today, I received several reports from Commander-in-Chief Syrskyi regarding the frontlines, our actions, and the push to drive the war onto the aggressor’s territory. I thank every unit of our Defense Forces that is making this possible. Ukraine is proving that it truly knows how… pic.twitter.com/qY81u1ahCl

— Volodymyr Zelenskyy / Володимир Зеленський (@ZelenskyyUa) August 10, 2024

Zelensky had previously alluded to the operation, praising the military’s ability “to surprise” and thanking them for taking Russian soldiers prisoner to be used in future negotiations, specifically referring to the past week.

In paying tribute to Ukrainian forces along the 1000km front line, Zelenskiy made special mention of actions in northern Sumy region, across the border from Russia’s Kursk region.

Russia has stepped up its attacks of guided bombs and other aerial strikes in Sumy, prompting mass evacuations.