Anthropic says Claude users in northern Yemen, territory controlled by Iran-backed Houthi rebels, tried to use the AI model to develop advanced missiles.
AI is already transforming warfare from Ukraine to Gaza, and its use on a rugged and remote battlefield is likely to increase concerns about its rapid spread.
Anthropic said the users of the accounts, which it blocked after identifying them, did not succeed in “fielding an operational device” but did carry out a failed test of a guided rocket. It said it knows that because the users returned to its Claude chatbot to find out why it failed.
In a report released Thursday, the company did not identify the users. But mountainous northern Yemen is controlled by Houthis, suggesting that the rebels are pursuing more sophisticated weapons at a time when they are already wielding an array of drones, missiles and other munitions in their campaign to seize more territory in Yemen and damage Saudi Arabia’s oil exports.
Hazam al-Assad, a member of the Houthis’ political bureau, said it is “unreasonable and illogical” that they would rely on open sources to develop and produce military capabilities.
“Our armed forces have modern, diverse and developed production capabilities and technology that it has accumulated over the period of Saudi aggression on Yemen,” al-Assad said, referring to the kingdom's involvement in Yemen's 12-year civil war. He said all weapons are used for self-defense.
The report was the third put out by Anthropic since March 2025 on global misuse of its AI platforms, and it described findings from December to August, ranging from state-sponsored groups spreading propaganda to unnamed actors researching how to make biological weapons more deadly.
The Houthis may have been seeking to develop their capabilities
The developer of the prominent Claude chatbot said it identified a cell in northern Yemen pursuing three different weapons programs, including a multi-variant missile that glides at hypersonic speed and a warhead that uses mobile phone hardware to maneuver mid-course.
It said the actors in Yemen used Claude Code instead of human software engineers to develop guidance, navigation and control software. Multi-variant missiles are ones in which different warheads and guidance systems can be fit on the same base design, a more economical way to build land, sea and air weapons.
Anthropic said it had evidence that before the accounts were banned, the users had already built an offline simulation tool kit that doesn’t use Claude or any other computing platforms.
Trevor Ball, a weapons analyst at Armament Research Services, said that while the Houthis “might be looking into hypersonic (missiles) by asking Claude,” they have nowhere near the production or technical capabilities to actually build them. He noted that U.S. hypersonic missiles “are still in testing.”
He said the Houthis already have Iranian-made anti-ship missiles with systems that allow the missiles to adjust guidance mid-course.
“They are probably just trying to develop their own capabilities more, so they are less reliant on Iranian shipments of weapons and components,” he said in a text message.
Iran has boasted it has hypersonic missiles and claimed it had fired them at Israel last year. It denies arming the Houthis, which would be in violation of a U.N. embargo, but Iranian weapons have been found on the battlefield and seized from shipments bound for Yemen.
The Houthis are increasingly threatening key shipping routes
The Houthis have launched waves of attacks on Saudi oil facilities and tankers in the Red Sea, threatening global trade as Iran continues to disrupt shipping in the Strait of Hormuz.
The rebels have made lightning territorial gains since Wednesday in their war with Yemen’s Saudi-backed government, seizing strategic territories along the Red Sea coast and in the Bab al-Mandeb Strait, a key alternative to the Strait of Hormuz.
Adam Baron, a Yemen-focused researcher at the New America think tank in Washington, said the Houthis have kept up with technological development.
“There’s a tendency to see the Houthis as this group of barefoot tribal fighters, and that’s just not true,” he said. “Whether it’s things like their emergent use of Claude, their use and manipulation of social media narratives or their ability to capitalize on the transfer of Iranian and wider axis expertise, we’re talking about an incredible — and deepening — amount of institutional tech savvy.”
The Houthis are known to have acquired and developed a sophisticated arsenal of weapons, including Iranian-made cruise and ballistic missiles with a range of more than 2,000 kilometers (1,200 miles) and unmanned submarines used in attacks.
Anthropic said it shared its findings with private and public partners.
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Fatma Khaled in Cairo contributed to this report.
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