Were you not aware of this? It was kept quiet, but not exactly secret.

> Since Crimea was annexed in 2014, the U.S. and partner militaries have helped grow Ukraine’s forces from just over 100,000 troops to nearly 250,000 [in 2017]. Just since January, Capt. Christopher’s unit of 250 soldiers has added another 3,000 or so Ukrainian soldiers to Kiev’s ranks.

https://www.defenseone.com/threats/2017/10/ukraine-us-trains...