Russia is finding it "significantly" harder to conduct combat operations against Ukraine because of a rise in Ukrainian long-range drone strikes on Russian weapons supplies, ammunition depots and fuel refineries, a senior commander has said.
Brigadier General Yuriy Shchygol signalled these attacks would grow, revealing that his country plans to more than quadruple the production rate of deep strike drones - with a range of hundreds of miles - to more than 2,000 aircraft a month.
Ukraine has been intensifying the tempo of its long-range drone strikes against targets inside Russia and Russian-occupied territory since late December - demonstrating what defence sources say is a world-leading capability that the Kremlin is struggling to counter.
The mission is an example of how Kyiv remains focused on combatting Moscow's invasion even as world attention fixates on the fallout from a row between Donald Trump and Volodymyr Zelenskyy, as well as efforts by Europe to prepare a plan for peace.
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The comments by Brigadier Shchygol, who coordinates long-range drone strikes for Ukraine's Defence Intelligence, offer a rare insight into the impact of the covert mission, which is also carried out by other branches of the Ukrainian military and security services.
"Russia is finding it increasingly difficult to conceal the extent of the damage," the commander told Sky News in an interview at an undisclosed location in Kyiv.
"Headquarters have been hit, command structures weakened, and panic is spreading among their officers. Compared to a year ago, conducting full-scale combat operations has become significantly more challenging for [the Russians]."
Sky News analysis of long-range drone strikes last month found that since December, there had been a ramping up of attacks against oil refineries in Russia that are used to fuel Russian tanks, jets and warships.
The analysis took in strikes officially confirmed by the Ukrainian armed forces. Brigadier Shchygol said "far more" drone attacks by Ukraine are not publicly confirmed.
In a sign of the importance placed on long-range drones, he said Kyiv's ability to manufacture this weapon has already jumped 100-fold since late 2022 to more than 500 per month.
While the officer would not say how many of these drones are then deployed on operations, he noted: "Nothing is just sitting in storage unused."
He said recent operations had targeted several storage sites for Russia's Iranian-designed Shahed one-way attack drones - used by the Russian armed forces against Ukrainian military and civilian targets.
More than 3,000 Shahed unmanned aerial vehicles were destroyed, according to the officer, who said: "As a result, their deployment of these drones has significantly decreased."
Top secret drone mission
Sky News was given rare access to view a drone mission last week at a top-secret area.
As night fell, soldiers dressed in black - all members of the Defence Intelligence of Ukraine, an elite branch of the armed forces - prepared a line of about 10 drones.
Each aircraft looked like a giant, grey metal mosquito.
The model is called "Lutti", which is Ukrainian for "Fury".
One by one, the drones burst into life, a propeller on the back whirring, pushing the aircraft forward at ever greater speed until it took off into the darkness.
We were told their target was an ammunition depot inside Russia.
"Vector", the commander on the ground, said his drones have a success rate of 70 to 80%.
He said Ukraine's deep strike operations are "very important".
"We change the war with these drones," Vector said, speaking with a balaclava pulled up to his eyes to protect his identity.
"We can show [Russia] that the war can come in their houses, in their towns, cities."
Russia's sheer size makes it vulnerable
Using drones to strike targets hundreds of miles inside Russia is a complex challenge.
But the sheer size of their enemy's country works in Ukraine's favour. The Russian military has weapons sites, ammunition storage areas, oil refineries and military headquarters dotted across its territory and lacks the air defences to be able to protect them all.
"We are reaching those targets. The slowing pace of their offensives - and in some places, even Ukrainian counter-offensives reclaiming territory - proves that our strikes are effective and growing more so," Brigadier Shchygol said.
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A huge planning and reconnaissance effort underpins Ukraine's long-range drone strikes.
It identifies targets and coordinates attacks between the different teams.
Varying volumes of drones are required for each mission - with some of the most complex strikes needing 100 unmanned aircraft.
From farm aircraft to fighter drone
The brigadier was speaking in a large room inside a disused building in Kyiv where five examples of different Ukrainian long-range drones were on display.
They tell the story of the evolution of vital battlefield technology that began life on a farm.
The earliest form of the long-range drone looks like an ordinary light aircraft, with rectangular wings and two propellers. It is a lot smaller than a manned plane but much larger than a regular drone - probably about the length of a car, with a similar wingspan.
This model, fitted with a camera and a large fuel tank to fly for long periods, had been used for surveillance for agricultural purposes.
It was adapted after Russia's full-scale invasion to conduct reconnaissance and even bombing missions.
The idea was then modified further to develop similar-sized drones that look more like fighter jets, with pointed noses and triangular wings. These were designed to hold explosives in the main body of the plane.
Some of the drones are remotely piloted, others work via autopilot.
Russia's war has forced Ukraine to use technology and innovation to fight back against its far more powerful foe.
It has accelerated the use of autonomous machines in an irreversible transformation of the warzone that everyone is watching and learning from.
Brigadier Shchygol said: "Right now, Ukraine's battlefield experience is essentially a manual for the world."
(c) Sky News 2025: Long-range drone strikes weakening Russia's combat ability, senior Ukrainian commander says