A satellite image of Engels airbase a day before the explosion (Picture: Schemes/ East2west News)

Vladimir Putin has started hiding his strategic nuclear bombers after a drone attack on an airbase in Russia, it has been reported.

A huge explosion was seen at the Engels airbase, near Saratov – hundreds of miles away from the border with Ukraine – in the early hours of Monday.

If confirmed that Ukrainian forces carried out the attack, it would be their deepest so far into the country and against key military facilities used in the war.

Two four-engine Tupolev Tu-95 bombers, which are the only propeller-powered strategic bombers still operational today, are believed to have been damaged.

As a result, the Russian leader is believed to have ordered the move of six planes from Engels.

The Moscow Times reported: ‘At least six strategic bombers were moved from the base in Engels to an unknown destination.’

Further satellite imaging shows a Tu-95 bomber with traces of fire-extinguishing foam on them (Picture: Schemes/ East2west News)

It is unclear where they have gone, but the assumption is the aircrafts, which are crucial to Putin’s nuclear strike capability, have been moved out of range of the Ukrainian drones.

A drill was also carried out at the airfield last night, suggesting the Russians are concerned about further attacks.

Ukraine is yet to officially comment on the explosion at Engels, and another at the Dyagilevo airbase in Ryazan.

But its air force wrote on Twitter on Monday evening: ‘Ryazan, Russia. What happened?’

More: News

It added a partying face emoji and images of what looked like a badly damaged aircraft.

Regardless if Ukraine is behind the two attacks, this is not what was supposed to happen as part of the Kremlin’s ’10-day invasion’ plan in February.

Week by week, there are yet more signs that Russia’s military machine cannot perform as advertised.

Get in touch with our news team by emailing us at [email protected].

For more stories like this, check our news page.

It is believed six planes have been moved from the airbase.