Russia is most likely preparing to try to transfer large numbers of reserve units to the Donbas.

This is according to a recent British Defense Ministry intelligence review.

Intelligence notes: Heavy shelling in the Donbas continues as Russia seeks to cordon off the Severodonetsk area through Izyum in the north and Popasna in the south.

It notes that the ability of both sides to form and deploy reserve units at the front is likely to become increasingly important to the outcome of the war.

Separately, British intelligence describes the situation with losses in the ranks of the self-proclaimed "DPR". 

Russian authorities have not published data on the total number of military losses in Ukraine since March 25. However, the pseudo-republic itself as of June 16 recognized 2,128 servicemen killed and 8,897 wounded since the beginning of 2022.

"The "DPR" loss rate is equivalent to about 55% of their initial strength, which underscores the extraordinary depletion of Russian and pro-Russian forces in the Donbass. There is a high probability that "DPR" forces are equipped with obsolete weapons and equipment," the intelligence agency states.

As a reminder, British Prime Minister Boris Johnson warned Britons that they should "prepare for a long war" as Putin resorts to a campaign of attrition.