The Yemen war has entered a potentially dangerous new phase.
Iran-backed Houthi militants have rapidly advanced along Yemen’s Red Sea coastline, capturing the strategic port city of al-Makha (Mocha), moving into Dhubab and reaching Mayyun (Perim) Island in the Bab al-Mandeb Strait, according to Yemeni government sources cited by Reuters. The developments could give the Houthis a much stronger position over one of the world’s most important maritime chokepoints.
The immediate confrontation is between the Houthis and the Saudi-backed, internationally recognised Yemeni government. But the stakes are considerably larger.
At one level, this is another chapter in Yemen’s decade-long civil war. At another, it is becoming a new front in the wider confrontation between Iran, the United States and their regional allies.
And another development makes the Houthi threat particularly striking: an Anthropic investigation has revealed that a Yemen-based weapons cell used Claude AI to help develop software for guided weapons and ballistic missiles.
Anthropic did not identify the cell as the Houthis. However, it described a group operating in northern Yemen, much of which is controlled by the Houthis, and documented an advanced missile-development effort. The circumstances make the Houthi movement the obvious focus of scrutiny, but the attribution should not be presented as confirmed by Anthropic.
What has happened on Yemen’s Red Sea coast?
The Houthis have spent years consolidating their control over northern and western Yemen. Their latest offensive represents something different: a push southwards along the Red Sea coast towards the Bab al-Mandeb Strait.
The group captured Mocha and subsequently advanced towards Dhubab, which lies directly on the Bab al-Mandeb. Houthi fighters have also reached Mayyun Island, which sits strategically inside the strait. Saudi-backed government forces reportedly withdrew from the island.
The geographical significance cannot be overstated.
Bab al-Mandeb is the southern gateway to the Red Sea. Ships travelling between the Indian Ocean and the Suez Canal have to pass through the area. At its narrowest point, the strait is only about 29 km wide, with Mayyun Island dividing the shipping channels.
The Houthis already control Hodeidah further north. Adding Mocha, Dhubab and potentially Mayyun to their sphere of control would give them a far more formidable position from which to threaten maritime traffic.
The Houthis have not formally announced that they control the entire Bab al-Mandeb, and reports about the extent of their control should therefore be treated with appropriate caution. But their latest territorial gains have clearly altered the strategic equation.
Why is Saudi Arabia at the centre of this crisis?
Saudi Arabia’s problem is directly connected to the Strait of Hormuz.
The ongoing US-Iran conflict has severely disrupted traffic through Hormuz, the crucial waterway between the Persian Gulf and the Gulf of Oman. Before the current conflict, roughly one-fifth of global oil shipments passed through the strait.
Saudi Arabia has consequently relied more heavily on an alternative route.
The kingdom’s East-West oil pipeline carries crude from the oil-rich eastern part of the country towards the Red Sea. From there, Saudi oil can be loaded onto tankers and sent towards international markets without passing through Hormuz.
But those tankers still depend on the Red Sea and, ultimately, Bab al-Mandeb.
That leaves Riyadh facing an uncomfortable strategic reality:
Iran has leverage over Hormuz, while the Houthis, whose movement is closely aligned with Tehran, are gaining leverage over Bab al-Mandeb.
Reuters reported that Saudi crude supply fell by 2.3 million barrels per day in August to about 6 million bpd, its lowest level in more than three decades. The International Energy Agency attributed part of the disruption to attacks on vessels transiting Bab al-Mandeb by groups linked to the Houthis.
Why does Iran matter?
The Houthi movement is part of Iran’s broader regional network of allies and aligned armed groups.
Tehran officially rejects the description of the Houthis as a conventional Iranian proxy and says the group makes its own decisions. However, Reuters reported that Iranian Revolutionary Guard personnel provided guidance during the latest Houthi offensive and that Iran had encouraged the Houthis to intensify pressure on Saudi Arabia. Iranian support has reportedly included weapons, funding and senior personnel.
For Tehran, the strategic benefit is obvious.
Iran does not necessarily need to directly close every shipping lane itself. If the Houthis can threaten traffic through Bab al-Mandeb while Iran keeps pressure on Hormuz, the combined effect could squeeze energy supplies from two sides of the Arabian Peninsula.
That is precisely why the latest Houthi advance is being watched far beyond Yemen.
The surprising AI angle: Houthis and Claude
The latest Anthropic threat report adds another dimension to the Houthi story.
Anthropic said it identified a threat-actor cell in northern Yemen running three weapons-development programmes.
One involved a guided rocket using a commodity, phone-class flight computer and terminal-phase guidance. Another involved a multi-stage ballistic missile with a stated range goal exceeding 2,000 km. The third was a multi-variant missile programme referred to as the “R2000” set, which included a proposed hypersonic-glide-vehicle variant.
The operators used Claude Code in place of human software engineers to develop guidance, navigation and control software.
Anthropic says Claude was used to help integrate an open-source autopilot with a phone-class flight computer, develop control and position-estimation software, tune controls, run firmware builds and conduct flight simulations. The operators reportedly ran multiple Claude instances simultaneously, effectively assigning different AI instances to coding, research and code review.
This is important because the AI was not simply being used to write a report about missiles.
It was being used to help develop the software responsible for steering and stabilising a flying weapon.
A guided rocket was actually test-fired
The operation also moved beyond simulations.
Anthropic said the Yemen-based actors conducted a live test of a guided rocket. The test appears to have failed, after which the operators returned to Claude to investigate the failure.
Anthropic stressed that it had no evidence that the actors successfully fielded an operational weapon. Nevertheless, the episode demonstrates how frontier AI can become part of an actual weapons-development workflow.
The company also found evidence that the actors had developed an offline simulation toolkit that could continue functioning without Claude.
That point is particularly significant. Banning an account does not necessarily eliminate the capability that has already been acquired.
How did they get around Claude’s safeguards?
Anthropic said its safeguards blocked many requests, but the operators found ways around them.
They concealed their ultimate objectives, disguised what the software would be used for and divided the work among multiple sessions so that no individual conversation necessarily exposed the complete weapons programme.
The company subsequently banned the associated accounts and shared threat intelligence with public- and private-sector partners. It has also introduced additional safeguards intended to detect weapons-development activity.
The episode illustrates a growing problem for AI companies: a request that appears innocuous in isolation can become dangerous when dozens or hundreds of apparently separate technical tasks are assembled into a weapons-development programme.
Why Bab al-Mandeb matters so much for global trade
Bab al-Mandeb is effectively a gateway between the Indian Ocean and the Suez Canal.
Disruption there can force ships travelling between Asia and Europe to take the much longer route around the Cape of Good Hope.
That means more fuel, longer journeys, higher insurance costs and increased freight rates.
The Houthis demonstrated this during their earlier Red Sea campaign, when major shipping companies rerouted vessels away from the area. Reuters notes that companies including Maersk, MSC, Hapag-Lloyd and BP previously diverted traffic because of Houthi attacks.
The latest territorial advance raises the possibility that the group could have an even greater ability to threaten the route.
And this time, the consequences could be amplified by the simultaneous disruption of Hormuz.
Saudi Arabia faces a difficult choice
Riyadh has already carried out strikes against Houthi targets, but it faces a dilemma.
A major Saudi military intervention could push the Houthis into intensifying attacks against Saudi oil infrastructure and shipping.
Doing too little, however, could allow the Houthis to consolidate their position along the Red Sea and around Bab al-Mandeb.
According to a Reuters report citing Axios, Saudi Crown Prince Mohammed bin Salman called US President Donald Trump twice and urged Washington to strike the Houthis. Trump reportedly rejected the request, with US officials saying Washington did not currently intend to launch direct military action against the Houthis.
The US is already heavily focused on Iran and the Strait of Hormuz. Opening another major front in Yemen could stretch American military resources and create another avenue for regional escalation.
For Riyadh, however, the stakes are existentially important.
Saudi Arabia is the world’s largest oil exporter, and its ability to move crude through alternative routes has become increasingly important because of the disruption around Hormuz.
Oil is where the Yemen crisis becomes everyone’s problem
The market has already reacted.
Brent crude was on track to end the week above $100 a barrel, while US diesel prices crossed $6 per gallon. The IEA has warned that global oil supply losses in 2026 could be considerably larger than previously expected as Middle Eastern conflicts continue disrupting energy flows.
The danger is not limited to crude.
Higher shipping costs and fuel prices feed into transportation, manufacturing, aviation, food prices and inflation.
In other words, a battle for a small strip of coastline in Yemen can eventually affect consumers thousands of kilometres away.
Is this becoming another Iran-Saudi confrontation?
In many ways, yes, but with an important distinction.
Saudi Arabia and Iran have historically competed for influence across the Middle East. Yemen became one of the most important theatres of that rivalry after the Houthis seized Sana’a and Saudi Arabia intervened militarily in 2015.
The current crisis is more dangerous because it is occurring against the backdrop of a much wider US-Iran confrontation.
The Houthi advance potentially gives Tehran another strategic pressure point without requiring Iran itself to directly fight Saudi Arabia.
Hormuz is Iran’s leverage. Bab al-Mandeb could become the Houthis’ leverage. Saudi Arabia sits between the consequences.
And the AI revelations add a troubling technological dimension to the equation. A militant organisation operating in one of the world’s most unstable regions is not merely acquiring conventional weapons; according to Anthropic, a Yemen-based cell was using a frontier AI system to accelerate the development of guidance software and missile simulations.
Anthropic has not confirmed that the cell was the Houthi movement. But the timing and geography make the revelation particularly significant as the Houthis expand their military footprint along Yemen’s Red Sea coast.
The immediate battle may be over Mocha, Dhubab and Mayyun.
The larger battle is over who controls the maritime arteries through which the world’s energy and trade move.
If the Houthis consolidate their hold over Bab al-Mandeb while Iran continues to restrict Hormuz, the Middle East will have entered a new and considerably more dangerous phase, one in which two critical global shipping chokepoints can potentially be used simultaneously as instruments of geopolitical pressure.
