By AFP and Focus | 2026-02-25

GENEVA, Switzerland -- The United States on February 23 accused China of dramatically swelling its nuclear arsenal and doubled down on claims that Beijing had conducted secret nuclear tests, demanding again that it be part of any future arms control treaty.

Washington said the lapse of New START on February 5, the last treaty between the United States and Russia, presented the possibility of striking a "better agreement" including Beijing.

Christopher Yeaw, the US assistant secretary of state for arms control and nonproliferation, told the Conference on Disarmament in Geneva that New START had been seriously flawed and "did not account for the unprecedented, deliberate, rapid and opaque nuclear weapons buildup by China."

"Despite its claims to the contrary, China has deliberately and without constraint, massively expanded its nuclear arsenal without transparency or any indication of China's intent or end point," he charged.

Chinese Ambassador for Disarmament Affairs Shen Jian told the conference that his country "firmly opposes the constant distortion and smearing of its nuclear policy by certain countries."

Parity estimate

But US officials "believe China may achieve parity within the next four or five years," said Yeaw, without elaborating on what he meant by parity.

Both Russia and the United States have more than 5,000 nuclear weapons, according to the Nobel Peace Prize-winning campaign group ICAN.

But New START, which expired on February 5, restricted the United States and Russia to 1,550 deployed nuclear warheads each, a number Washington charges Russia has passed and China is fast approaching.

"Beijing is on track to have the fissile material necessary for more than 1,000 nuclear warheads by 2030," Yeaw said.

"China's nuclear arsenal is not in the same league as the countries possessing the largest nuclear arsenals," said Shen. "It is not fair, reasonable or realistic to expect China to participate in the so-called trilateral talks."

But some discussions are under way, said a senior US State Department official, who asked not to be identified.

A "preparatory" meeting took place with a Chinese delegation in Washington on February 6, the day after New START expired, and a more "substantive" meeting was scheduled in Geneva on February 24, the official told reporters.

The expiration of New START marks the first time in decades that there is no treaty to curtail the positioning of the planet's most destructive weapons, sparking fears of a fresh arms race.

Yeaw welcomed the lapse of the treaty. Its numerical limits on warheads and launchers were "no longer relevant," given Russia's alleged violation of the agreement, said Yeaw.

Moscow is helping "boost Beijing's ... arsenal size," he said.

Accusations of secret Chinese tests

The United States is not "walking away from or ignoring arms control," Yeaw said, insisting: "Quite the opposite is true."

The diplomat reiterated on February 23 US contentions that China had carried out secret nuclear tests.

He provided more details on a low-yield test Washington says Beijing conducted in 2020 and accused China of preparing more explosions with larger yields.

Yeaw told the conference that data gathered in nearby Kazakhstan showed China conducted a 2.75-magnitude explosion underground on June 22, 2020.

"The estimated yield of the event was a 10 tons nuclear explosion, or five tons conventional equivalent, which assumes the explosion was fully coupled in hard rock below the water table," he said.

And "there have been others," the senior US official said. "China has planned to conduct tests with designated yields in the hundreds of tons."

"Our goal is a better agreement toward a world with fewer nuclear weapons," Yeaw emphasized.