President Donald Trump has called on US military leaders to resume testing US nuclear weapons in order to keep pace with other countries such as Russia and China.

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 weapons testing since 1992.

This announcement comes just days after Trump denounced Russia for testing a nuclear-powered missile, which reportedly has an unlimited range.

Later, on Air Force One after the two leaders' meeting, Trump stated that the specific nuclear test sites would be determined at a later time. With others doing testing, I think it's appropriate that we do also, he commented on his way back to Washington.

While no country except North Korea has conducted a nuclear test explosion in this century, Trump's declaration marks an apparent reversal of a long-standing US policy. The last US nuclear weapons test took place in 1992, during the administration of former President George HW Bush, who implemented a moratorium as the Cold War ended.

Trump's announcement drew immediate criticism. Daryl G Kimball, executive director of the Arms Control Association, termed Trump's statement as misinformed. The US has no technical, military, or political justification for resuming nuclear explosive testing for the first time since 1992, he noted.

This significant policy shift has raised concerns about instigating a new wave of nuclear testing globally, potentially undermining decades of non-proliferation efforts.

Furthermore, Trump's remarks come roughly 100 days before the expiration of the New Strategic Arms Reduction Treaty (New Start) in February 2026, which governs the number of nuclear warheads each country can deploy.

Despite the gravity of resuming nuclear tests, Trump's post acknowledged the tremendous destructive power of such weapons, suggesting a pressing need to update the US nuclear arsenal in light of international developments.