Guo said China, as a “responsible nuclear-weapon state” and a permanent member of the United Nations Security Council, has maintained its long-standing nuclear test moratorium and upheld its no-first-use policy on nuclear strikes.

Russia is testing nuclear weapons, and China is testing them too, you just don’t know about it,” Trump said in an interview that aired Sunday.

China is emerging as a fierce competitor to the US in the race to build small modular reactors and fusion that can help power data centers.