What Happened
- President Donald Trump and Chinese President Xi Jinping held a phone call on February 4, 2026, which Trump described as "excellent." The call covered trade, Taiwan, the Russia-Ukraine war, Iran, and US purchases of Chinese oil and gas.
- Xi Jinping reasserted China's stance on Taiwan, cautioning Trump on arms sales to Taiwan, while Trump pushed for trade deals and urged Beijing to break from Tehran.
- A planned Trump visit to China in April 2026 was discussed, with both sides signalling interest in managing trade tensions.
- Separately, the US government alleged that China conducted secret nuclear explosive tests, including a yield-producing test on June 22, 2020, with yields in the hundreds of tons.
- US Undersecretary of State for Arms Control Thomas DiNanno made the allegations at the Conference on Disarmament in Geneva. China denied the claims. An independent review of publicly available seismic data found no signature of an explosive test near China's Lop Nur test site for that date.
Static Topic Bridges
Comprehensive Nuclear-Test-Ban Treaty (CTBT)
The CTBT was adopted by the United Nations General Assembly on September 10, 1996, and opened for signature on September 24, 1996. It bans all nuclear explosions, whether for military or civilian purposes. However, the CTBT has not entered into force because ratification by all 44 Annex 2 states is required. As of 2026, eight Annex 2 states have not ratified: the US (signed but not ratified), China (signed but not ratified), India (not signed), Pakistan (not signed), Israel (signed but not ratified), Egypt (signed but not ratified), Iran (signed but not ratified), and North Korea (not signed).
- CTBT adopted: September 10, 1996; opened for signature: September 24, 1996
- Annex 2 states: 44 states that possessed nuclear power or research reactors at the time, whose ratification is required for entry into force
- Signatories: 187 states; ratified by: 178 states (as of 2025)
- CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization): headquartered in Vienna; operates the International Monitoring System (IMS) with 321 monitoring stations worldwide
- IMS uses four technologies: seismological, hydroacoustic, infrasound, and radionuclide monitoring
- India's position: has not signed the CTBT; considers it discriminatory; maintains a voluntary moratorium on nuclear testing since the Pokhran-II tests (May 1998)
Connection to this news: The US allegations that China conducted a yield-producing nuclear test, if true, would constitute a violation of the spirit of the CTBT, even though the treaty has not entered into force. The distinction between subcritical tests (which do not produce a nuclear chain reaction and are not prohibited) and yield-producing tests (which do) is at the heart of the dispute.
US-China Strategic Competition and Nuclear Balance
The US-China strategic rivalry encompasses trade, technology, Taiwan, and increasingly, nuclear weapons. China has been expanding its nuclear arsenal significantly, moving from an estimated 350 warheads in 2023 to a projected 1,000 by 2030, according to the US Department of Defense. This represents a shift from China's traditional "minimum deterrence" posture. The US maintains approximately 5,550 total nuclear warheads (with approximately 1,700 deployed strategic warheads).
- China's estimated nuclear warheads (2023): approximately 500; projected to reach 1,000 by 2030 (US DoD estimate)
- US nuclear warheads: approximately 5,550 total; approximately 1,700 deployed strategic
- China's nuclear doctrine: No First Use (NFU) policy, declared since 1964 (first nuclear test)
- China's nuclear test site: Lop Nur, Xinjiang (active 1964-1996; 45 tests conducted)
- US nuclear test site: Nevada National Security Site (formerly Nevada Test Site)
- New START treaty (US-Russia): limits deployed strategic nuclear warheads to 1,550 each; China is not a party
- India's nuclear doctrine: No First Use (NFU), credible minimum deterrence
Connection to this news: The US allegations of secret Chinese nuclear testing come in the context of China's rapid nuclear arsenal expansion. If China is testing new warhead designs, it would represent a qualitative leap beyond the quantitative expansion already documented, raising concerns about the stability of the nuclear balance in Asia and globally.
Taiwan Issue in US-China Relations
Taiwan (officially the Republic of China) has been a core flashpoint in US-China relations since 1949. The People's Republic of China considers Taiwan a breakaway province that must eventually be reunified, by force if necessary. The US follows a "One China Policy" (distinct from Beijing's "One China Principle"), acknowledging Beijing's position but maintaining unofficial relations with Taiwan, including arms sales under the Taiwan Relations Act (1979).
- US One China Policy: based on three joint communiques (1972 Shanghai, 1979 Normalisation, 1982 Arms Sales) and the Taiwan Relations Act (1979)
- Taiwan Relations Act (1979): commits the US to provide Taiwan with "arms of a defensive character" and to maintain capacity to resist coercion
- Six Assurances (1982): US commitments to Taiwan including no end date for arms sales and no prior consultation with Beijing on arms sales
- Taiwan Strait crises: 1954-55, 1958, 1995-96, and heightened tensions in 2022 (Pelosi visit)
- India's position: follows One China Policy but has not reiterated it formally since 2010; maintains unofficial relations with Taiwan through Taipei Economic and Cultural Center in New Delhi
Connection to this news: Xi Jinping's reassertion of the Taiwan stance during the phone call reflects Beijing's consistent messaging on its "core interest." Trump's engagement on trade and Iran during the same call illustrates the multi-dimensional nature of US-China competition, where nuclear, trade, and Taiwan issues are increasingly interconnected.
Key Facts & Data
- Trump-Xi phone call: February 4, 2026
- CTBT adopted: September 10, 1996; not yet in force (requires ratification by all 44 Annex 2 states)
- Annex 2 states that have not ratified CTBT: US, China, India, Pakistan, Israel, Egypt, Iran, North Korea
- China's nuclear warheads (estimated 2023): approximately 500; projected 1,000 by 2030
- China's Lop Nur test site: 45 nuclear tests conducted (1964-1996)
- China's No First Use (NFU) policy: declared since 1964
- India's Pokhran-II tests: May 11 and 13, 1998; India maintains voluntary testing moratorium
- US allegations of Chinese nuclear test: June 22, 2020 (yield in hundreds of tons, per DiNanno)
- CTBTO IMS: 321 monitoring stations using seismological, hydroacoustic, infrasound, and radionuclide technologies
- Taiwan Relations Act: enacted 1979; governs US unofficial relations with Taiwan