"Because of other countries testing programs, I have instructed the Department of War to start testing our Nuclear Weapons on an equal basis," he wrote on social media just before meeting with Chinese President Xi Jinping in South Korea.
The US has more nuclear weapons than any other country, Trump said, with Russia second and China a "distant third". It has not conducted nuclear testing since 1992.
It comes just days after Trump denounced Russia for testing a nuclear-powered missile. The Kremlin says its tests were "not nuclear"
