Russia is holding back on using its most advanced fighter jets over Ukraine because it's scared they'll get shot down, UK intel says

• Russia's using its most advanced combat jets against Ukraine, British intelligence said Monday.
• But the jets are firing missiles into Ukraine only from Russian territory, the brief added.

Russia is holding back on using its most advanced fighter jets over Ukrainian airspace because it's scared they'll get shot down, the UK's defense ministry said on Monday.

In its latest intelligence update, the defense ministry said Moscow had "almost certainly" used Su-57 Felon fighter jets to conduct missions against Ukraine since at least June.

"These missions have likely been limited to flying over Russian territory, launching long range air-to-surface or air-to-air missiles into Ukraine," the brief said.

It suggested that Russia's keeping its jets on home soil because it's "avoiding the reputational damage, reduced export prospects, and the compromise of sensitive technology which would come from any loss of FELON over Ukraine."

The twin-engine and single-seat aircraft is Russia's most advanced fifth-generation supersonic combat jet.

For an aircraft to be considered fifth-generation, it must possess specific technical characteristics such as the ability to fly at supersonic speeds without afterburners.

The defense ministry cited a satellite image taken on December 25 indicating that five of the jets were housed at the only known Felon air base in Russia, in the southern region of Akhtubinsk.

Russia's defense minister, Sergei Shoigu, said in August that the Felon had already been used "brilliantly" in combat since Russia's invasion, though there was little evidence at the time that this was the case.

Russia's wary tactic is indicative of its continued risk-averse approach to employing its air force in the war against Ukraine, given the risk of significant losses.

The General Staff of the Armed Forces of Ukraine said in an update on Monday that Russia had lost more than 280 airplanes since the beginning of its full-scale invasion of Ukraine.