A Ukrainian military source told Sky News: “A Ukrainian Air Force (UAF) mission has struck a Russian command node in Belgorod.

“Whilst damage assessment is still occurring, it is confirmed as a direct hit. This is the first UAF air-delivered munition delivered against a target within Russia.”

It was not immediately clear what weapon the Ukrainian pilot had used to carry out the attack, but the US and France recently announced they had relaxed rules to allow Kyiv to use them to strike targets inside Russia.

Regardless of the weapon, it would have been a daring sortie to fly because of Russia’s multiple layers of long- and medium-range air-defence systems positioned on the border.

Ukrainian pilots have become accustomed to flying at death-defyingly low altitudes to use the terrain to mask their route and limit the range of oncoming surface-to-air missiles. The raid could have been connected to an earlier cross-border strike on a Russian S-300 or S-400 air-defence battery.

First major long-range attack

Geolocated footage indicated that a Ukrainian Himars rocket launcher destroyed two launchers and damaged a command post belonging to the system, the Institute for the Study of War think tank reported last week.

The strike is one of the first major long-ranged attacks on Russian soil with US-donated weapons after President Joe Biden authorised their use to protect against Moscow’s offensive into the northeastern Kharkiv region.

Kyiv’s forces have previously capitalised on Russia seemingly failing to replace its air-defence systems after the incumbent battery had been destroyed. The most notable example came when Ukraine used Storm Shadow missiles to strike the headquarters of Russia’s Black Sea Fleet in Sevastopol. A week before the attack, Ukraine’s navy claimed to have destroyed a S-400 surface-to-air missile system on the Crimean peninsula.

Justin Crump, an analyst, said: “The heavier Russian air defence forces certainly seem to lack agility and Ukraine has exploited this to the maximum. They’ve been caught napping when they shouldn’t have been.”

Chechen capture claims denied

Meanwhile, Volodymyr Zelensky denied claims that Chechen special forces had captured a village in a cross-border raid in the north-eastern Ukrainian Sumy region.

Ramzan Kadyrov, the Chechen warlord, claimed his forces had seized the frontier settlement of Ryzhivka. But Mr Zelensky said that Kyiv’s troops were “in full control” and a Russian sabotage group operating there had been “destroyed”.

“As for the village of Ryzhivka, the occupier tried to implement a propaganda operation there,” the Ukrainian president added on Monday. “As of this morning, the Russian flag in the village was destroyed, and there is no occupant presence.”

Kadyrov had said fighters from his Akhmat battalion “together with servicemen from other Russian units carried out tactical operations and liberated another settlement of the enemy”.

Authorities in Sumy have been braced for a potential attack across their border since Russia opened a new front in the war with an advance on the neighbouring Kharkiv region, capturing several towns.

Ukraine has since managed to halt the advance as supplies and troops were rushed to the battle, and US President Joe Biden granted permission for American-donated weapons to be used to hit targets on Russian soil.