Given the collapse of the New START nuclear treaty this month, the timing of Washington's latest and provocative charge leveled at Beijing is curious and interesting...

The United States’ top nuclear arms has "accused China of carrying out an undisclosed nuclear detonation in 2020, arguing that recent secretive underground tests by China and Russia have given Washington reason to conduct 'parallel steps' as a decades-long moratorium on nuclear testing among major powers is unraveling," The Washington Post has reported.

It was last Friday that US undersecretary of state for arms control and international security, Thomas DiNanno, declared in Geneva that "The US government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tonnes."

DiNanno then alleged that "yield-producing tests" were conducted on June 22, 2020 in a highly unusual accusation given the precision and specificity of it, even down to the day.

China belatedly responded several days later, on Wednesday formally rejecting the allegation of secretive nuke testing. Taking note of the end of New START between Moscow and Washington, Chinese foreign ministry spokesman Lin Jian called it "an excuse" to justify Washington's own potential return to nuclear testing.

"The United States has persistently distorted and smeared China’s nuclear policy," he said on Wednesday. According to more via state-run Xinhua:

Responding to a relevant query at a regular press briefing, spokesperson Lin Jian said persistent U.S. distortion and smearing of China's nuclear policy essentially constitutes political manipulation, which is aimed at pursuing nuclear hegemony and evading its own nuclear disarmament responsibilities.

"China firmly opposes this," Lin said, stressing that the United States is the biggest source of disruption to both the international nuclear order and global strategic stability.

Lin noted that by allowing the New START Treaty to expire without renewal, the United States has severely undermined mutual trust among major countries and shaken global strategic stability. 

President Trump has long wanted a more comprehensive international nuclear treaty which takes into account China's growing stockpile - though it remains that Russia and the US are far and away the biggest armed nuclear powers. No other country even comes to these Cold War era rivals and superpowers.

Meanwhile, the Taiwan issue still looms large for Beijing, which has been busy warning Washington over Trump-approved record-breaking arms packages.

It has been many months since China launched any of its notorious 'encircling drills' to put a check on Taiwan. Should US arms keep pouring into Taipei, such large-scale sea and aerial drills could again become a reality, strongly signaling Washington to halt such 'separatist' activities.