UKRAINIAN special forces reportedly hid deep inside Russian territory to guide drone blitzes in a humiliating blow to Vladimir Putin.
Another Russian airfield was blasted by a suspected Ukrainian drone strike on Tuesday - just a day after two of Putin's nuke bombers were reportedly blown up.
Shocking footage showed an explosion and a huge fireball at the military airbase in the Kursk region on the border with Ukraine.
An oil tank was reportedly on fire on the airport - and the blaze was said to still be raging more than ten hours after the attack.
Thick black smoke filled the sky and covered almost 5,500sq ft as more firefighters raced to the scene to control the inferno.
Kursk regional governor Roman Starovoyt said: "An oil tank is on fire as a result of a drone attack near the Kursk airfield. There are no casualties. The fire is currently being localised."
Read more on the Ukraine war
Suspected Ukrainian drones also targeted the Belbek military airport in Sevastopol - but were reportedly downed by air defences.
It comes a day after Ukraine launched drone strikes on two Russian military bases hundreds of miles inside the country.
The Engels airbase and the Ryazan airfield are between 300 and 450 miles from the Ukrainian border - beyond the range of any known missile in Ukraine’s arsenal.
A senior Ukrainian official said the drones were launched from Ukrainian territory - but at least one strike was made with the help of special forces close to the base who helped guide the drones to the target, reports.
Most read in The Sun
A fuel truck exploded at the airfield in Ryazan, a base for Russian special forces, after the strike - killing three people and injuring five.
Images also showed significant damage to a nuclear-capable Tu-22M3 bomber.
Two of Putin's Tu-95 nuke bombers were also reportedly blown up in another Ukrainian drone attack at the Engels airbase in the Saratov region.
The bombers have been used to blast targets in Ukraine with non-nuclear weapons, particularly in recent weeks as Putin continues to blitz the country's infrastructure.
Two Russian troops were injured and rushed to hospital after the suspected Ukrainian strike, Visegrád 24 reports.
Russia claims Ukraine has used the Soviet reconnaissance drone Tu-141 called Strizh to mount the string of attacks.
The Russian defence ministry claimed the drones were hit by their air defences - but falling debris caused damage to the aircraft on the ground.
The UK's Ministry of Defence said the military "is likely to respond by temporarily moving bombers to dispersal airfields".
"The causes of the explosions have not been confirmed," it said.
"However, 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."
Ukraine’s government has not publicly acknowledged the strikes.
A report from Readovka warned Moscow could be under attack if the strikes are coming from Ukraine.
It said: "If the drone came from Ukraine, then our enemy already has technology with a range of 1000km, which means that Moscow could be under attack.
"There is only one conclusion: counter-terrorism measures on the territory of the Russian Federation should be strengthened to the maximum, retaliation strikes should be continued tenfold.
“Until the Russian response has a massive effect, such attacks will continue."
Saratov regional governor Roman Busargin said there was "no cause for concern" after the Engels airbase strike.
He said: "Information about a loud explosion and outbreak in Engels in the early hours of this morning is spreading on social media and the media.
"I would like to assure you that no emergencies have occurred in the residential areas of the city.
"There is no cause for concern. No civilian infrastructure was damaged."
READ MORE SUN STORIES