Belarusian involvement in an expanded Russian war against Ukraine would risk bringing the end of dictator Alexander Lukashenko’s regime, U.S. officials warned the strongman in response to the deployment of Russian forces in Belarus.

“I believe Belarus’s complicity in such an attack would be completely unacceptable to Belarusians and to many inside the regime, as well as to us and our allies and partners,” a senior State Department official told reporters. “And we’ve made our concerns known to the Belarusian authorities privately.”