Russia has been embarrassed by another drone attack which analysts say exposes a significant failure to protect home soil and raises the spectre of a strike on the capital Moscow.

The latest fiery attack in the Kursk region, near the border with Ukraine, set an oil storage tank ablaze.

It came a day after Russia blamed Ukraine for audacious drone attacks deep in its territory at two military airfields. Russia said three servicemen were killed.

The strikes demonstrate an apparent new ability of Ukraine to penetrate hundreds of kilometres into Russian air space.

Ukraine has not responded to the accusations, but the hits are considered unprecedented and once again raise the question of an escalation of the war.

Russian commentators said on social media that if Ukraine could strike that far inside Russia, it might also be capable of hitting Moscow.

Thick black smoke billows over Kursk, in Russia, after an apparent drone strike. Photo: Twitter screenshot

Analysts say Russia’s inability to protect itself from such low-tech incursions is embarrassing evidence of its flagging military capabilities.

The UK Defence Ministry characterised the strikes as one of Russia’s most significant strategic failures.

“If Russia assesses the incidents were deliberate attacks, it will probably consider them as some of the most strategically significant failures of force protection since its invasion of Ukraine,” the ministry said.

“The Russian chain of command will probably seek to identify and impose severe sanctions on Russian officers deemed responsible for allowing the incident.”

Asked about the strikes, Ukrainian Defence Minister Oleskiy Reznikov repeated a longstanding joke blaming carelessness with cigarettes.

“Very often Russians smoke in places where it’s forbidden to smoke,” he said.

Officials in the Russian city of Kursk, located close to Ukraine, released pictures of black smoke above an airfield in the early morning hours of Tuesday after the latest strike.

The governor said an oil storage tank there had been set ablaze but there were no casualties.

Kursk Region Governor Roman Starovoit said an oil tank caught fire near an airfield. Photo: Getty

POW swap

As the third Russian airfield was aflame, Russia and Ukraine  exchanged 60 prisoners of war each in the latest of a series of such swaps.

Russia’s defence ministry said the 60 freed Russian soldiers would be flown to Moscow to receive medical care and psychological support.

Ukraine’s presidential chief of staff Andriy Yermak hailed the returning Ukrainians as heroes and said they included dozens who had held out in the city of Mariupol — including the besieged Azovstal steelworks — until Russia forced its surrender in May.

“We continue to return the defenders of Mariupol — in today’s ‘list of 60’ there are 34 of them, including 14 from Azovstal. Some are wounded, and will receive all the necessary help in Ukraine,” Mr Yermak said.

Airbase attacks

The New York Times, citing a senior Ukrainian official, said the drones involved in Monday’s attacks on two air Russian bases at Ryazan and Saratov were launched from Ukrainian territory.

The Times said at least one of the strikes was made with the help of special forces close to the base.

Ukraine did not directly claim responsibility for any of the attacks. If it was behind them, Monday’s strikes would be the deepest inside Russia since Moscow invaded Ukraine on February 24.

Israeli satellite imaging company ImageSat International shared images it said showed burn marks and objects near a Tu-22M aircraft at the Dyagilevo airbase.

‘Acts of terrorism’

Russia’s defence ministry said Monday’s attacks were acts of terrorism intended to disable long-range aircraft and the low-flying drones were shot down.

The deaths were reported on the Ryazan base, 185km southeast of Moscow.

Saratov is at least 600km from the nearest Ukrainian territory.

Ukrainian military analyst Serhiy Zgurets said the air force bases hit on Monday were the only facilities in Russia that could fully service bombers used to launch attacks on Ukraine.

“It is still too early to say what is at issue here but the ability of the armed forces of Ukraine to reach military targets deep in the territory of the Russian Federation has a very symbolic and important meaning,” he wrote on the Espreso TV website.

Russia responded to Monday’s attacks with a “massive strike on the military control system” and other targets using high-precision air and sea-based weapons in which all 17 objectives were hit, Russia’s defence ministry said.