- [Narrator] These satellite images
show the Engels air base,
a strategic hub for Russian forces,
before and after it was hit by a strike.
Following the explosion, there are fewer aircraft left
and what looks like damage to the tarmac.
The base is located
more than 350 miles away from the Ukrainian border.
It's one of multiple blasts
that have recently hit military bases
and fuel storage sites in Russia
as well as Russian troops in Ukraine,
including the deadliest known strike in months.
The attacks highlight how combat is not just playing out
along the front lines.
Targeted strikes like this one
on another Russian air base
have taken on a big role in the war.
Aviation and security experts
say the images reveal Russia struggled
to protect its military assets
and Ukraine's tactics to destabilize its enemy.
The Engels Airfield is the main operating base
of long-range aviation in Russia.
- Engels has been used as a launchpad
for Russia's near daily
or sometimes weekly air raids across Ukraine.
- [Narrator] In these satellite images
taken in early December,
more than 30 Russian war planes can be seen at the base.
That includes 19 TU-95s,
strategic bombers capable of carrying nuclear weapons.
Aviation experts from Janes, an intelligence firm,
and CNA, a security think tank, analyzed the images.
They said the planes are located closely together
without cover,
indicating they aren't prepared for any type of strike
- Military, and also, imagine they must have assumed
that 350 miles into its own territory was safe.
- [Narrator] But shortly after a first blast hit the base,
(explosion echoing)
the sound of the explosion was recorded
by security cameras nearby.
Russia didn't immediately respond to a request for comment
about whether it was prepared.
Moscow sent a statement
that Ukrainian drones were intercepted by its air defenses
and the wreckage hit the facility,
killing three Russian servicemen.
Kyiv hasn't claimed responsibility for the strikes,
but Ukraine's forces have hinted
that they're capable of launching them.
Military analysts said images taken after the explosion
show it appears to be firefighting foam
underneath one bomber
and a possible impact site next to it.
Days later, Moscow appeared to have taken measures
to try and protect its assets.
On December 12th,
pictures show that nine fewer TU-95 aircraft
are at the base.
The Ukrainian Ministry of Defense
said the planes have been relocated,
and military analysts say the wider spacing
between the planes and the newly erected barriers
are strategies to protect the hub from attacks.
Russia didn't immediately respond
to a request for comment about those planes.
Weeks later, another security camera captured the sound
of a second strike at the same base.
(explosion echoing)
With its soldiers being hit by strikes in military bases
where they're supposed to be relatively safe,
analysts say Ukraine hopes to undermine the morale
of Russian troops.
- This campaign is also part of another front in the war
playing away far from the front lines.
- [Narrator] In Ukraine, Russia's been shelling
a number of military and civilian buildings
and infrastructure.
But since the early days of the war,
Kyiv has been working to show
that it's also capable of destabilizing the invader.
- In April, Ukraine hit the the flagship
of the Russian Black Sea Fleet, the Moskva, sinking it,
which was the first big shock that Ukraine could do this.
It also hit a bridge that Putin opened
from Russia to Crimea.
- [Narrator] Several of those Ukrainian attacks
prompted Moscow to retaliate
with heavy barrages of missiles,
diverting attention and resources from the front lines.
Strikes like this one on another airfield in Russia
can also be hard to detect,
complicating Russia's operations.
Moscow accused Ukraine of hitting its bases
with Soviet-designed jet drones that fly at a low altitude.
Military analysts point out
it's difficult to independently verify
what weapons were actually used,
and that makes it more difficult for Russia
to anticipate future strikes on its own territory.
Russia, on its end,
also continues to use missiles and drones
to strike power stations and other infrastructure in Kyiv
and other parts of Ukraine,
causing blackouts and disrupting life across the country.
But the strikes hitting its military
have affected operations.
And now that bases closer to Moscow are being hit,
military analysts say Russia is being forced
to spread out its already stretched defenses.