Ukraine cannot have US contractors on the ground or even Polish but heck Iran and other countries no problem for Russia.
"The U.S. has evidence that Iran sent troops to Ukraine to help Russia
launch drone attacks on targets across the country, Biden administration officials said Thursday.
Iran sent trainers and technical support to enable Russian forces to use
Iranian-made drones “with better lethality,” John Kirby, White House National Security Council spokesperson, told reporters in a teleconference.
“We assess that Iranian military personnel were on the ground in Crimea and assisted Russia in these operations,” Kirby said.
“The systems themselves were suffering failures and not performing to the standards that apparently the customers expected,” Kirby said. As a result, the Iranians decided to send in troops to assist the Russians, he said.
Asked how many Iranians were in Crimea and why, Kirby said, “I don’t have a number … What we do know is there’s a relatively small number that are.”"
https://www.nbcnews.com/politics/na...a-use-iranian-made-drones-biden-adm-rcna53277