MOSCOW: Russia said on Thursday that it would beef up border defences, improve command and control and send in additional forces nearly 10 days after Ukraine made the biggest attack on Russian sovereign territory since World War II.

The lightning incursion into Russia unfurled on August 6 when thousands of Ukrainian troops smashed through Russia's western border in a major embarrassment for President Vladimir Putin's top military brass.

Russia's military is yet to explain in public how Ukrainian forces were able to carve out a slice of the world's biggest nuclear power.

Putin's Defence Minister Andrei Belousov, said the general staff had prepared a series of measures to defend Russia's border regions of Kursk, Bryansk and Belgorod — which cover an area the size of Portugal.

"First of all, we are talking about improving the effectiveness of the command and control system in cooperation with other law enforcement agencies," Belousov was shown telling top generals and officials from the Belgorod region.

While the Ukrainian attack has revealed weaknesses in Russia's border defences and changed the public narrative of the conflict, Russian officials said what they cast as a Ukrainian "terrorist invasion" would not change the course of the war.

Russia, which invaded Ukraine in 2022, has been advancing for most of the year along the 1,000km (620-mile) front in Ukraine and has a vast numerical superiority. It controls 18% of Ukraine.

War

On the ground in the Kursk region, where Ukraine has carved out at least 450sq-km (175sq-miles) of Russian territory, both Ukraine and Russia claimed successes.

Russia said it had regained control of the settlement of Krupets in the Kursk region.

"We have burned everything that moves, everything that we have been able to find," Major General Apti Alaudinov, who commands Chechnya's Akhmat special forces who are fighting in Kursk.

Ukraine's top commander, Oleksandr Syrskyi said Ukraine had advanced 1.5km over the past 24 hours and had set up a military commandant's office to ensure order.

A source in the Ukrainian Security Service said a group of more than 100 Russian soldiers had been captured. Separately, a Ukrainian minister said Kyiv was carving out a buffer zone to protect its population against attack.

Ukraine said there was no sign Russian military pressure was receding along the eastern front, and reported the heaviest fighting in weeks near Pokrovsk. 

Russia said it had taken control of a village just 16km (10 miles) from the city, which sits abreast of major roads that supply Ukrainian forces in the area.