According to Ukrinform, the UK Ministry of Defense reported this on Twitter.
"In the face of combat losses, it is likely that Russia is struggling to maintain stocks of UAVs, exacerbated by component shortages resulting from international sanctions," the ministry said.
It added that the limited availability of reconnaissance UAVs is likely degrading commanders' tactical situational awareness and increasingly hampering Russian operations.
Read also: Over 50,000 Russian invaders already killed in UkraineAccording to the report, in recent years, Russian doctrine has given an increasingly prominent role for UAVs, particularly to spot targets for its artillery to strike.
"UAVs can be vulnerable to both kinetic effects – where they are directly shot down – and to electronic jamming," the ministry said.
Ukraine's Armed Forces killed about 50,150 Russian invaders from February 24 to September 6, including 350 in the past day alone.