The update also warned that Russia still make further territorial gains, their rate of advance is likely to be very slow without a significant operational pause for reorganisation.
The updated from the MoD reads: “Russia continues to commit what are nominally six separate armies to its Donbas offensive. At full strength, before the invasion, these formations were established for around 150,000 personnel.
"In recent weeks, Russia has often operated with company-sized groupings of around 100 personnel when undertaking offensive operations in any one sector at a time.
"Russia has struggled to sustain effective offensive combat power since the start of the invasion and this problem is likely becoming increasingly acute.
"As well as dealing with severe under-manning, Russian planners face a dilemma between deploying reserves to the Donbas or defending against Ukrainian counterattacks in the southwestern Kherson sector.
"Russia’s stated immediate policy objective is to seize all of Donetsk Oblast."
It continued: “While Russia may still make further territorial gains, their operational tempo and rate of advance is likely to be very slow without a significant operational pause for reorganisation and refit.”
Ukrainian President Volodymyr Zelensky expanded the shakeup of his security services on Monday by suspending 28 more officials, a day after he dismissed two senior officials over allegations that their agencies harboured “collaborators and traitors”.
In his nightly video address, Mr Zelensky said a “personnel audit” of the Security Service of Ukraine (SBU) was underway, and the dismissal of the 28 officials was being decided.
“Different levels, different areas of focus. But the reasons are similar — unsatisfactory results of work,” Mr Zelensky said.
Analysts said the moves are designed to strengthen Mr Zelensky’s control over the army and security agencies, which have been led by people appointed before the Russian invasion began on February 24.
Russia has pressed forward with its missile and shelling attacks over the last few days throughout the country, which Ukrainian officials said were designed to intimidate the civilian population and create panic.