Russian planes keep getting blown up in airfields hundreds of miles from the fighting, exposing embarrassing gaps in its defenses

• Multiple military aircraft have been damaged or destroyed in Russia this month.
• It is the latest in a series of similar incidents highlighting the vulnerability of its air force.

Russian military aircraft keep getting damaged or destroyed at airbases deep inside its own territory, exposing gaps in its defenses that Ukraine has been able to exploit.

Military analysts told The Wall Street Journal that Ukraine has likely disabled more Russian aircraft while they were sitting in bases than it had in live combat. It is a situation that will likely prove embarrassing for one of the world's foremost military powers.

The latest damaged aircraft are four transport planes damaged in a drone attack at an airport in the city of Pskov in north-west Russia, including two that were on fire, according to state media outlet TASS.

It is around 450 miles from the Ukrainian border.

Russia's foreign ministry blamed Ukraine, saying it "will not go unpunished," Reuters reported.

It followed a string of attacks on aircraft at bases within Russia and its occupied territory this month.

A prized supersonic Russian Tupolev Tu-22 bomber was blown up earlier this month at the Soltsky-2 airfield in Russia's Novgorod region, which is also more than 400 miles from the border.

Russia's defense ministry blamed a Ukrainian drone for that attack too.

Around the same time, Ukraine carried out a drone strike on a third facility, the Shaykovka base, where at least one aircraft was damaged. That base was closer, but still 130 miles from the border.

A fourth attack was earlier in August — satellite photos suggested that at least nine Russian planes were damaged or destroyed in Saky airbase in Crimea, around 100 miles from Ukrainian-held territory.

At the time Eliot Higgins, founder of investigative website Bellingcat which often covers Russia, said he "can't think of a time Russia has lost this many air assets in one day in recent memory."

There are broadly two ways to hit distant airfields like this — either of them bad for Russia.

Ukraine could fire drones or missiles from its own territory, which involves defeating Russia's supposedly competent air defense.

Or it could deploy people far enough behind enemy lines to do the attacks at shorter range, defeating its supposedly competent border defenses and security services.

The details of the attacks are rarely clear, but UK intelligence said the attack on the Soltsky-2 airfield was likely launched from within Russian territory.

The attacks prompted recrimination in Russia.

The Institute for the Study of War, a respected US think tank, said that Russian military bloggers criticized officials for not storing aircraft properly using hangars that might have kept them safer.

The ISW said the reaction shows how "such deep attacks support larger Ukrainian efforts to degrade Russian morale."

Ukrainian drone attacks have also touched Moscow in recent weeks, in some cases prompting its airports to close down.

Russia has blamed Ukraine for most of them, but Ukraine has often not taken responsibility, in keeping with a general policy of rarely acknowledging attacks on Russian soil.

Rebel groups within Russia have occasionally taken responsibility for attacks, but not the recent hits on airfields.

Russian officials said on Wednesday that Ukrainian drones were fired at multiple Russian regions: Pskov, Bryansk, Kaluga, Orlov, Ryazan and Moscow, Reuters reported.