The US has seen “some evidence” of improvement in Russia’s ability to combine air and ground operations, as well as its capacity for resupplying forces in the field, officials say.

The progress is “slow and uneven,” a senior US defense official said, allowing Russian forces to advance only “several kilometers or so” each day.

But the US assesses that Russia is trying to learn from the mistakes it made early on, where columns of tanks and armor ran out of food and fuel, leaving them easy prey to Ukrainian hit-and-run tactics.

Russia has placed command and control elements near its border with eastern Ukraine, according to a senior NATO official, a sign they are attempting to fix the communications and coordination failures observed in the attack on Kyiv.