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

Washington said the lapsing earlier this month of New START — the last treaty between top nuclear powers 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 non-proliferation, 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 build-up 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.

Risk of ‘escalation’ if Iran attacked: deputy foreign minister

In response, Chinese ambassador Shen Jian told the conference: “The US has made groundless accusations that China has conducted a nuclear test,” adding that Beijing “firmly opposes the constant distortion and smearing of its nuclear policy by certain countries”.

Risk of ‘escalation’

Iran’s deputy foreign minister Kazem Gharibabadi warned of a wider escalation if his country was attacked, after US President Donald Trump raised the threat of strikes.

“We call upon all nations committed to peace and justice to take meaningful steps to prevent further escalation,” Gharibabadi said at the Conference on Disarmament in Geneva.

“The consequences of any renew­ed aggression wouldn’t remain confined to one country — and responsibility would rest with those who initiate or support such actions.”

“The Islamic Republic of Iran remains committed to diplomacy and dialogue as the most effective path towards de-escalation and sustainable security,” Gharibabadi said.

Gharibabadi said that while Tehran sought the path of diplomacy, it was prepared to defend its sovereignty, territory and people, insisting it would exercise its right to self-defence “if necessary”. He said meaningful progress in disarmament and non-proliferation could only be achieved through mutual, balanced and legally-binding commitments.

He called upon nuclear weapons states to engage constructively in talks towards a comprehensive nuclear weapons convention, plus offer legally-binding security assurances for countries without nuclear weapons.

Parity

Yeaw said US officials “believe China may achieve parity within the next four or five years”, 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 Feb 5, restricted the United States and Russia to 1,550 deployed nuclear warheads each — a number Washington says China is fast approaching.

Published in Dawn, February 24th, 2026