British defense officials say deaths and injuries of Russian military personnel are surging as Moscow intensifies its offensive ahead of the first anniversary of its invasion of Ukraine.

The British defense ministry said in its intelligence update on Sunday that "Russia has likely suffered its highest rate of casualties since the first week of the invasion."

The ministry also said statistics by the Ukrainian General Staff indicate that the "average for the last seven days was 824 casualties per day, over four times the rate reported over June-July 2022."

The ministry analyzed that "the uptick in Russian casualties is likely due to a range of factors including lack of trained personnel, coordination, and resources across the front."

The US-based Institute for the Study of War said on Saturday that Ukrainian military officials and others are "downplaying Russia's ability to launch a sweeping large-scale offensive."

The think tank also said the morale of Russian frontline soldiers is sagging.