Volodymyr Zelensky has hailed the “absolutely brilliant” operation against Russian warplanes, saying it will “undoubtedly be in history books”.

“A result achieved solely by Ukraine. One year, six months, and nine days from the start of planning to effective execution. Our most long-range operation,” Mr Zelensky said.

The Ukrainian agents involved in the operation were successfully extracted from Russian territory, he added.

Appearing to refer to the fact that a limited number of videos have so far been released - with analysts saying they cannot independently verify Kyiv’s claim that 41 planes were destroyed - Mr Zelensky said: “I instructed the Security Service of Ukraine to inform the public about the details and results of the operation that can be disclosed. Of course, not everything can be revealed at this moment, but these are Ukrainian actions that will undoubtedly be in history books.”

In a later post on X, Mr Zelensky claimed one third of Russian strategic cruise carriers had been destroyed.“In total, 117 drones were used in the operation with a corresponding number of drone operators involved. 34 per cent of the strategic cruise missile carriers stationed at air bases were hit. We will continue this work.”

Nato should prepare for a possible attack from Russia within the next four years, Germany’s chief of defence has told the BBC.

Russia is producing hundreds of tanks per year, which could be used for an attack on Nato Baltic state members before 2029, General Carsten Breuer said.

Nato is facing a “very serious threat” which is more significant than General Breuer has seen in his four decades of service, he told the BBC at the Shangri-la Dialogue, a defence summit in Singapore.

Russia is producing nearly 1,500 battle tanks per year, he added.

"Not every single tank is going to [the war in] Ukraine, but it's also going in stocks and into new military structures always facing the West," he said. "There's an intent and there's a buildup of the stocks.”

A source from Ukraine’s SBU security agency has claimed an airfield more than 4,000 kilometres inside Russia was struck, in what has been hailed as an unprecedented wave of drone strikes.

Here’s what the source told The Kyiv Independent about how the attack was carried out.

Volodymyr Zelensky shared details of Kyiv's drone swarm attack that left Russia stunned with the loss, reportedly, of 40 planes, including strategic bombers.

“Today, a brilliant operation was carried out. The preparation took over a year and a half. What’s most interesting, is that the 'office' of our operation on Russian territory was located directly next to FSB headquarters in one of their regions,” he said in his nightly address on X.

“In total, 117 drones were used in the operation with a corresponding number of drone operators involved. 34 per cent of the strategic cruise missile carriers stationed at air bases were hit. We will continue this work.”

A Ukrainian drone attack destroyed more than 40 Russian planes deep in the country’s territory, Ukraine's Security Service said on Sunday, while Moscow pounded Ukraine with missiles and drones just hours before a new round of direct peace talks in Istanbul.

In his evening address on Sunday, Volodomyr Zelensky said that 117 drones had been used in the operation. He claimed the operation had been headquartered out of an office next to the local FSB headquarters, the Russian intelligence and security service.

Former foreign secretary James Cleverly said Ukraine's latest drone attack, which reportedly destroyed 40 aircraft deep inside Russia, showed the war-hit nation "WILL NOT GIVE UP!"

"Ukraine’s drone attack shows that those who have written them off were wrong to do so. I’ve been to Ukraine, met people at every level of society and I learned one big lesson. THEY WILL NOT GIVE UP!" he said on X.

Russia's security service FSB thwarted an attempted arson attack on railway transportation in the far eastern region of Primorsky Krai, or Primorye, that was to be conducted on Ukraine's order, the RIA news agency reported today.

"It was established that two 19-year-old residents of Primorsky Krai, on orders from Ukrainian special services and expecting to receive a monetary reward, committed actions aimed at setting fire to track-side relay cabinets," RIA cited the service as saying.

Ukraine’s destruction of more than 40 Russian warplanes would be “really, really significant” if the scale of damage claimed by Kyiv is true, a military analyst has told The Independent.

“If the 40 hits are confirmed then it is really, really significant, and a very successful operation,” said Emil Kastehelmi of the Black Bird Group.

The Finnish open-source intelligence organisation has only confirmed six hits so far, but Mr Kastehelmi expects that number to rise.

“Even if it’s just [the six hits which Black Bird Group has confirmed], it’s is still a very successful operation,” he said.

“It’s been done in an interesting way, operating deep inside Russia with FPV [first-person view] drones, which the air defense can’t quickly and very effectively act against whilst they are there.”

The operation may not have gone entirely to plan, Mr Kastehelmi, said. It is “very likely” that one or two of the trucks carrying the drones into Russia exploded before they could reach their targets.