Russia’s Latest Nuclear Saber-Rattling: Nuclear Testing

Critical Questions by Heather Williams and Lachlan MacKenzie

Published November 5, 2025

In a November 5 meeting of the Security Council of Russia, President Vladimir Putin directed his military and political leaders to "submit coordinated proposals on the possible first steps focusing on preparations for nuclear weapons tests." Putin's comments come a week after President Trump posted on social media that he had "instructed the Department of War to start testing our Nuclear Weapons on an equal basis. That process will begin immediately." On the one hand, Putin's comments fit a wider pattern of nuclear saber-rattling tied to the ongoing war in Ukraine. On the other hand, these statements continue to ratchet up nuclear risks and undermine the existing nuclear order. Approximately six hours prior to Putin's statements, the United States conducted a test of its Minuteman III intercontinental ballistic missile (ICBM).

We are at risk of escalation by testing. The best way to prevent Russia from resuming explosive nuclear testing is not only for the United States and other nuclear possessors to continue to observe the testing moratorium, but also for the wider international community to hold Russia and China accountable for their suspected low-yield testing in violation of the Comprehensive Test Ban Treaty (CTBT). The majority of signatories to the treaty agree with the U.S. interpretation that it obligates states to observe a "zero-yield" ban on nuclear testing. Trump's recent comments, along with reports from the intelligence community, indicate Russia and China have not been meeting these terms. This rhetorical spat could either escalate to a return to nuclear testing or be an opportunity for strengthening the non-testing norm and highlighting Moscow and Beijing's ongoing nuclear antagonism.

Q1: What did Putin say about nuclear testing?

A1: At the November 5 meeting, Putin called for "proposals on the possible first steps . . . on preparations" for tests. Effectively, he requested suggestions for potential initial preparations for nuclear testing. Importantly, he did not order Russia's Ministry of Defense to actively begin preparing for resumed testing. Kremlin spokesperson Dmitry Peskov subsequently reinforced this point, explaining that "the president did not give instructions to begin preparations for testing . . .The president instructed that the advisability of beginning preparations for such tests be considered." The Kremlin does not frequently publish transcripts of Security Council meetings, and the choreographed nature of the conversation indicates that Putin intended it as a signal.

Putin made clear that Russia would not resume nuclear testing unless the United States did so first, saying, "I would like to note that Russia has always strictly adhered to its obligations under the Comprehensive Nuclear-Test-Ban Treaty, and we do not plan to abandon these obligations. At the same time . . . if the United States or any other state party to the Treaty was to conduct such tests, Russia would be under obligation to take reciprocal measures." This framing is consistent with Putin's past comments on nuclear testing. In his 2023 address to the Federal Assembly, he asserted that "some politicians in Washington are already pondering live nuclear tests" and warned that "[Russia] will not be the first to proceed with these tests, but if the United States goes ahead with them, we will as well."

The November 5 meeting also highlighted confusion about the United States' intentions. Several of Putin's deputies expressed uncertainty about the meaning of Trump's statements on nuclear testing. Chief of the General Staff Valery Gerasimov, for example, acknowledged the "absence of an official explanation from the American side" but maintained that the General Staff's analysis "indicates Washington's intent to prepare for and conduct such tests." The head of Russia's Foreign Intelligence Agency similarly commented that U.S. officials had "declined to provide a substantive reaction" to Russia's questions about Trump's statement, and the chair of Russia's Security Council admitted that "we are not entirely clear about the United States' future plans and steps regarding nuclear weapons testing." Putin's call for "additional information on this matter" suggests that Russia is unlikely to resume nuclear testing without greater clarity about U.S. plans.

Q2: Why would Russia test a nuclear weapon now?

A2: If the United States resumes nuclear testing, Russia will likely follow suit to deny the United States a unilateral advantage. Putin and his deputies frame U.S. testing as a threat to the strategic balance, and reciprocal Russian testing as a way to address that threat. In his 2023 address, Putin concluded his comments on nuclear testing with a warning that "No one should harbour dangerous illusions that global strategic parity can be disrupted," implying that he views U.S. nuclear testing as a threat to strategic stability. Russian Defense Minister Andrei Belousov framed the issue similarly during the November 5 meeting, saying that "the [United States'] possible withdrawal from the moratorium on nuclear weapons testing would be Washington's completely logical step toward undermining the global system of strategic stability."

Testing could also provide Russia with another tool for its coercive toolkit. Russia has used nuclear signaling to coerce the United States and its allies throughout the war in Ukraine. For example, when announcing the invasion, Putin threatened that countries that intervened would suffer "consequences . . . such as you have never seen in your entire history." Given the current deadlock in negotiations and intensified U.S. sanctions on Russia, the Kremlin might seek to use explosive nuclear testing, paired with rhetoric, exercises, and other signals, to coerce the United States into abandoning Ukraine or imposing a lopsided peace deal.

Q3: When was the last time Russia tested a nuclear weapon?

A3: Russia last conducted an explosive nuclear test in October 1990; however, for years, the U.S. Department of State and the Intelligence Community have raised concerns about low-yield nuclear testing. Instead of explosive testing, Russia has been accused of conducting supercritical tests. For example, a 2019 Defense Intelligence Agency director alleged that, "Russia is probably not adhering to the nuclear testing moratorium in a manner consistent with the zero-yield standard." And compliance reports by the U.S. Department of State continue to raise concerns about Russian low-yield testing and a lack of transparency at the Novaya Zemlya test site. For example, the most recent report said there were no new compliance developments, but noted, "previous reports have assessed that Russia has conducted supercritical nuclear weapons tests without TTBT notification since renewing its nuclear explosive testing moratorium in 1996. Concerns remain due to these past activities and the uncertainty and lack of transparency relating to Russia's activities at Novaya Zemlya."

"Nuclear testing" can refer to at least four different potential activities. First would be explosive nuclear testing that produces a seismic yield, and could be detected by the Comprehensive Test Ban Treaty Organization monitoring stations, along with other tools. Other than North Korea, no state has conducted an explosive nuclear test since the 1990s. A second type of activity would be supercritical nuclear testing, which would produce a self-sustaining chain reaction but not necessarily a seismic yield. This could be interpreted as a violation of the CTBT (more on that below). A third type of test would be a subcritical test, which most nuclear possessors already conduct to ensure the reliability of their nuclear arsenals. This is typically done through supercomputing and high-powered lasers, such as the U.S. National Ignition Facility, the United Kingdom's Orion laser at the Atomic Weapons Establishment, or China's laser facility in Mianyang. Russia has been developing the Tsar Laser, which would be the most powerful laser in the world, but Russia has faced major challenges with its completion.

A final potential form of testing, and what many suspected President Trump's comments were in reference to, is the testing of nuclear delivery platforms. Here, Russia has shown a bevy of activity in recent months. Just two weeks ago, Russia tested its nuclear-powered and nuclear-capable Burevestnik cruise missile, which Putin claimed traveled 14,000 kilometers and has long-loiter capabilities. Putin claimed Russia had also tested its Poseidon underwater drone, nuclear-capable. While the United States is not conducting supercritical tests, as Russia is believed to be, it does regularly test its nuclear delivery platforms. For example, the same day as Putin's comments, November 5, the United States test-launched a Minuteman III ICBM.

Q4: Could Russia test a nuclear weapon before the United States?

A4: Probably, but it would depend on the type of test. In recent years, Russian officials have repeatedly talked about preparing for nuclear testing. In 2023, Mikhail Kovalchuk, a close adviser to Russian president Vladimir Putin, suggested Russia should test "at least" one nuclear weapon at the former nuclear testing site, Novaya Zemlya. A week before Kovalchuk's statement, CNN released satellite imagery to reveal the expansion of Novaya Zemlya facilities over the past three years to include a new building, along with expansions at former test sites in China and the United States. In 2024, another senior Russian official said the test site was "fully ready" and could resume "at any moment."

But in the recent Security Council meeting, General Gerasimov offered a more nuanced interpretation and said, "the time required to prepare for nuclear tests, depending on their type, ranges from several months to several years." It's worth noting, however, that Gerasimov offered these comments to recommend taking "appropriate measures" immediately to prepare for nuclear testing. These statements were likely in reference to explosive testing, given the long-standing suspicion that Russia has been conducting supercritical testing.

Conversely, the United States maintains a 36-month test readiness for explosive testing and has not made investments in preparing to test since 2010. The United States has not needed to test nuclear weapons, and returning to testing could undermine U.S. national security interests. Political and scientific leaders have repeatedly confirmed that the United States does not need to return to explosive tests to ensure the reliability of the nuclear arsenal. Additionally, if the United States tests, Putin has indicated Russia would follow suit, and China likely would do the same. With far fewer tests than Russia or the United States, China would stand to gain the most from testing. A return to explosive testing would also raise domestic political challenges within the United States, as members of Congress may be reluctant to have their states play host to testing. A return to explosive nuclear testing could also undermine existing nuclear modernization plans by drawing resources and personnel.

Q5: How can the United States convince Russia not to resume nuclear testing?

A5: Putin's comments suggested Russia would only return to explosive testing if the United States tested first. But the underlying meaning of President Trump's initial comments remains opaque, and it's unclear if or how the United States would return to testing. Given that Russia is likely conducting supercritical testing, according to Department of State Compliance Reports, in violation of the CTBT, this could mean the United States would also start low-yield testing and abandon its zero-yield interpretation of the CTBT. Or it could mean Trump wants to increase testing of nuclear delivery platforms. The opacity of comments on both sides raises the risks of misperception and preemptive testing or testing preparations. Further information about the direction of U.S. policy will help to clarify the risks of escalation moving forward.

Heather Williams is the director of the Project on Nuclear Issues and a senior fellow in the Defense and Security Department at the Center for Strategic and International Studies (CSIS) in Washington, D.C. Lachlan MacKenzie is a research associate with the Project on Nuclear Issues in the Defense and Security Department at CSIS.

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