U.S. President Donald Trump announced that he had directed the Department of Defense to begin new nuclear tests “on equal footing” with Russia and China, without specifying a time or location.

The statement, posted on Truth Social ahead of his meeting with Chinese President Xi Jinping, was seen as a show of strength before the summit.

Although Washington, Moscow, and Beijing signed the Comprehensive Nuclear-Test-Ban Treaty in 1996, the treaty has yet to enter into force as some major powers, including the U.S., have not ratified it.