Russian troops have also been much less mobile than Western observers expected at the outset of the war, largely sticking to roads while Ukrainian forces lie in wait. The British Ministry of Defence’s internal intelligence agency said on Wednesday that Ukrainian troops “have adeptly exploited Russia’s lack of [maneuver], frustrating the Russian advance and inflicting heavy losses on the invading forces.” A British intelligence assessment released Wednesday also indicated that Russia has been forced to divert troops to defend supply lines against Ukrainian attacks…

On Thursday, a senior U.S. defense official said Russia’s consideration of bringing in new troops and supplies to reinforce more than 100 battalion tactical groups already in the country indicated that the Kremlin “was beginning to get concerned about the longevity” of its forces in Ukraine. One European diplomat, who spoke to Foreign Policy on condition of anonymity to give a candid military assessment, said Russia has begun to lose enough troops in combat to have a real impact on its ability to carry out offensive operations, and Russian troops on the front lines are beginning to worry about how long they can hold out.

“The Russian troops on the ground definitely think like that. The Russian generals probably think like that,” the European diplomat said. “But whether or not this is getting to Putin or whether he’s listening to this is another matter.”