Christopher Yeaw, assistant secretary of State for the Bureau of Arms Control and Nonproliferation, spoke to a U.N.-backed ...

Remarks by a top administration official appeared to be aimed at dispelling skepticism of its assertions, as President Donald Trump vows to restart U.S. tests.

A Trump administration official said that a remote seismic station in Kazakhstan measured an “explosion” in western China on ...

While China is expanding its nuclear arsenal at a dramatic pace, Russia and the U.S. are also testing new delivery platforms.

The allegations were leveled by U.S. officials late last week. Arms control experts worry that norms against nuclear testing are unraveling.

US intelligence agencies believe that China is developing a new generation of nuclear weapons and has conducted at least one covert explosive test in recent years as part of a broader push to ...

President Donald Trump wrote on Truth Social, his social media site, that he had instructed the Department of War (formerly the Defense Department) to return to “nuclear testing” — although it’s ...

Resuming full testing of nuclear weapons — as President Donald Trump called for last week — would be unnecessary, costly, undermine nonproliferation efforts, and empower the nation’s adversaries to ...

US President Donald Trump has shocked the world by announcing another nuclear bomb test. There's no doubt that countries like China, North Korea, and Russia are secretly conducting nuclear tests.