Russian forces still face logistical challenges in their offensive, a Pentagon official says.

Russian forces are making “slow and uneven” progress in fierce fighting in the Donbas region of eastern Ukraine, but are still struggling to overcome the same supply line problems that hampered their initial offensive, a senior Pentagon official said on Thursday. 

...Russian troops have made “incremental” progress but nowhere near enough to seize an overall advantage, the official said.

“The Russians haven’t overcome all their logistics problems,” the official said, citing slow going on the shipment of food, fuel, weapons and ammunition, despite having much shorter supply lines now than they did during the war’s first several weeks...Moscow now has 92 battalion groups fighting in eastern and southern Ukraine — up from 85 a week ago, but still well below the 125 they had in the first phase of the war...

Just over 20 additional battalions remain in Russia in various states of combat readiness, resupplying and rearming in a patchwork of units that were badly damaged by the earlier fighting, the official said. The remainder of the original 125 battalions are most likely destroyed, and American and British officials estimate that more than 15,000 Russian soldiers have died in the war since it began