A senior U.S. defense official says the Pentagon has determined that some of the Russian combat units that retreated from the Kyiv area in recent days are so heavily damaged and depleted that their combat utility is in question.

The official described these units as “for all intents and purposes eradicated, with only a small number of functioning troops and weapons remaining.

The official did not say how many units sustained such extensive damage, but noted some combat units that withdrew from the Kyiv area are beginning to move toward into Russia for refitting and resupplying before likely deploying to the Donbas region of Ukraine.

The official also said the U.S. has seen thousands of additional Russian troops added to the combat force in and around the Ukrainian city of Kharkiv.

All told, the U-S believes Russia has lost 15 to 20 percent of the combat power it had assembled along Ukraine’s borders before launching its invasion February 24th.