Attacks on a “sensitive” air base near Moscow are “likely to be of most strategic concern” for Russian leaders, according to UK intelligence.

The ministry of defence (MoD) explained in its daily update that “both Russia and Ukraine have experienced unusually intense attacks deep behind their lines” over the last four days.

Moscow launched a wave of missile attacks across Ukraine earlier this week, targeting six cities including the capital of Kyiv.

It came just as the Ukrainian president Volodymyr Zelenskyy was denouncing Russia in a speech to the UN’s General Assembly, on International Day of Peace.

While much of the war has taken place on Ukrainian soil, attacks in Russia have become increasingly common in recent months as Kyiv hits back – and this week was especially eventful, according to the MoD.

In a post shared on X, formerly Twitter, the UK intelligence officers claimed: “There have been reports of explosions at Russian logistics sites, air bases and command posts in Crimea, the Krasnodar region and near Moscow.”

Crimea is the Ukrainian peninsula which Russia illegally annexed in 2014 but which Kyiv is determined to retrieve.

The Krasnodar region is to the south of the Ukraine-Russia border, while Moscow, the capital, is much further north and deeper within Russia.

The MoD continued: “It is highly likely that Russia’s Black Sea Fleet has again been heavily targeted.

“However, the explosions at Chkalovsky Air Base, near Moscow, are likely to be of most strategic concern to Russian leaders.”

The UK intelligence officers claimed that this is a “sensitive location” because it’s where Russia stores its military aircrafts and VIP transport for Russian leaders.

The MoD noted that Moscow responded quickly: “Russia has launched long-range strikes at targets across Ukraine repeatedly over the last week.

“This unusual intensity is likely partially in response to the incidents in Russia and Crimea.

“With the ground battle relatively static, each side is seeking advantage by striking through their adversary’s strategic depth.”

Ukraine’s highly-anticipated counteroffensive has made slow progress in recent months, despite claims that it has broken through the Russian defensive lines in some places.

Ukraine has also faced pushback from Poland over its grain exports this week, with Warsaw announcing it plans to stop sending weapons to its beleaguered neighbour.