A U.S. official focusing on arms control has provided what he called new, declassified details of a Chinese underground nuclear test nearly six years ago.

WASHINGTON — The United States is ready to carry out low-yield nuclear tests to match alleged secret explosions by China and ...

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

Remarks by a top administration official appeared to be aimed at dispelling skepticism of its assertions, as President Donald ...

US official Christopher Yeaw said 'Beijing is on track to have the fissile material necessary for more than 1,000 nuclear ...

The US accused China of secret nuclear tests, banned under international agreement, that were building toward tests of larger nuclear warheads.

Officials have ruled out earthquakes or mining as the source of a 2.75-magnitude event in 2020 near China's nuclear test site.

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 ...

Speaking before the Conference on Disarmament in Geneva, Russian ambassador Gennady Gatilov decried US President Donald Trump ...

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

WEST PALM BEACH, Fla. (AP) — New tests of the U.S. nuclear weapons system ordered up by President Donald Trump will not include nuclear explosions, Energy Secretary Chris Wright said Sunday. It was ...