The expiration of the New START treaty between the US and Russia has heightened fears of a renewed nuclear arms race. China is rapidly expanding its nuclear arsenal, projected to exceed 1,000 warheads by 2030, while refusing to join voluntary limitation talks. A senior US official has accused China of conducting a secret "yield-producing" nuclear test in June 2020, alleging efforts to conceal it from seismic monitoring. However, the CTBTO stated its monitoring system did not detect any such event, and the US has not provided public evidence to support its claim.

As New START expires, China's rapid nuclear buildup and alleged secret 2020 test raise global arms control concerns. US officials make claims, but evidence is disputed.

The New START agreement between the USA and Russia is dead, and there are concerns this will lead to a nuclear-testing resurgence. Simultaneously, China spurns invitations to join a voluntary nuclear limitation treaty with the world's largest nuclear powers.

As New START - the Treaty between the USA and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms - expired on 5 February 2026, the USA has been calling for a new nuclear-arms control treaty encompassing itself, Russia and China.

The latter has been conducting the world's fastest-ever expansion of a nuclear arsenal. The People's Liberation Army Rocket Force (PLARF) had an estimated nuclear-warhead stockpile "in the low 600s" by late 2024, according to a Pentagon report issued last December. Maintaining this blistering pace, the Pentagon predicted China will reach more than 1,000 warheads by 2030.

At its 3 September 2025 parade in Tiananmen Square, China proudly strutted five nuclear-weapon types: DF-61, DF-5C and DF-31BJ intercontinental ballistic missiles(ICBM); JL-1 air-launched nuclear-tipped missiles; and JL-3 submarine-launched missiles. The Pentagon estimates the PLARF has 400 ICBMs and 550 intermediate-range ballistic missiles in service. China also has three massive missile silo fields in Hami, Yumen and Yulin containing 320 silos.

The Federation of American Scientists estimates the USA and Russia have about 4,000 warheads each. Incidentally, the American arsenal has decreased in recent years, whereas Russia's has been growing.

Notably, Washington DC accused China of secretly conducting a "yield-producing nuclear test" in 2020. This is despite Beijing claiming a moratorium on such activities and being a signatory to the Comprehensive Nuclear Test Ban Treaty (CTBT), even though it never ratified it.

Thomas DiNanno, the US Under Secretary of State for Arms Control and International Security, said at the Conference on Disarmament in Geneva on 6February: "Today, I can reveal that the US government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tons. The PLA sought to conceal testing by obfuscating the nuclear explosions, because it recognized these tests violate test ban commitments."

DiNanno continued, "China has used decoupling - a method to decrease the effectiveness of seismic monitoring - to hide its activities from the world. Chinaconducted one such yield-producing nuclear test on June 22nd of 2020."