CHINA yesterday rejected unsubstantiated accusations from US President Donald Trump that it has resumed secret nuclear weapons tests.

Mr Trump, who alarmed the world on Thursday with threats to resume such tests — no major power has detonated a nuclear weapon since the 1990s — claimed in an interview on Sunday that Russia, China, Pakistan and North Korea were all secretly testing nuclear weapons.

“I don’t want to be the only country that isn’t testing,” he said, although US Energy Secretary Chris White said the same day that he believed Mr Trump’s threat to resume testing referred to “systems tests… not nuclear explosions.”

Mr Trump has himself refused to be drawn on his exact meaning, telling journalists who asked whether he meant exploding nuclear devices that they would “find out very soon.”

North Korea is the only country to have conducted nuclear weapons tests since the establishment of the Comprehensive Test Ban Treaty, to which it is not a signatory. Its tests have been detectable through seismic sensors and atmospheric monitoring of radioactive particles, which suggests if China, Russia and Pakistan were secretly conducting tests as alleged by Mr Trump these would be difficult to conceal.

China’s Foreign Ministry spokeswoman Mao Ning said yesterday China had strictly honoured the moratorium on nuclear tests and reminded the world that China, unlike the other four nuclear weapons states on the UN security council, is committed to a no-first-use policy on nuclear weapons.

Russia says it has not conducted any nuclear tests either, but would resume them if the United States does.