Yemen's Houthi movement has seized two strategic Red Sea islands and tightened its grip on the country's western coastline, marking a dramatic shift in the decade-long conflict and raising alarm well beyond Yemen's borders. The group captured the Greater and Lesser Hanish islands, located roughly 160 kilometres north of the Bab al-Mandab strait — the narrow chokepoint connecting the Red Sea to the open ocean — following earlier seizures of the port city of Mokha and Perim island in the strait itself. The advance has effectively handed the Iran-backed group control over a vital artery for global shipping and Saudi Arabia's oil exports to Asian markets.

Saudi Arabia, which backs Yemen's internationally recognised government, warned on Tuesday it would respond "firmly" to Houthi attacks after a series of ballistic missile and drone strikes wounded 13 civilians in the kingdom's south. Civil defence alerts were issued for six Saudi cities, including Yanbu — the kingdom's main Red Sea oil export terminal — before authorities issued an all-clear later in the day. The Houthi leadership has stated it is not seeking to block all commercial shipping, but is targeting Saudi-linked vessels specifically, as part of a maritime blockade the group declared against Riyadh in July when Yemen's civil war reignited after a 2022 ceasefire largely collapsed.

The human cost of the renewed fighting has been severe. Nearly 94,000 people have been displaced inside Yemen since hostilities escalated this month, according to the International Organization for Migration, with around 200 schools converted into emergency shelters in the country's southwest. More than 2,000 people have crossed the Bab al-Mandab strait by sea to reach Djibouti, a small country on the Horn of Africa, where authorities have deployed naval and coast guard assets to conduct rescue operations. The Houthi advance now places their forces just 32 kilometres from a US military base in Djibouti. "This is the second time in my life that I've been displaced," said Hussein Haydara, a man from Hodeidah. "We were terrified of the shelling and sniper fire."

The strategic implications extend well beyond Yemen. The Houthi seizure of Red Sea chokepoints compounds pressure on global oil supply at a moment when the wider US-Iran war has already severely disrupted traffic through the Strait of Hormuz, with commodity vessel transits there falling to just four on Monday. Analysts warn that the combination of Houthi control over Red Sea routes and the damage to Saudi Arabia's east-west oil pipeline — struck separately by Iran-aligned Iraqi militias — threatens to remove millions of barrels per day from global markets. Brent crude rose to $106.92 a barrel on Tuesday morning, while average diesel prices in the United States hit $6 per gallon for the first time last week. Energy market analysts caution that the supply buffers that had previously cushioned global markets from price spikes have now largely been exhausted.

Security analysts say the swift Houthi advance — capitalising on the broader regional chaos unleashed by the US-Iran conflict — poses a fundamental question about what, if anything, can halt their momentum. With the Strait of Hormuz severely disrupted, the Red Sea route the Houthis now dominate had become the critical alternative for Saudi oil exports to Africa and Asia. Iraqi militias meanwhile continue to signal they will retain their weapons even as US forces complete their withdrawal from Iraq by a September 30 deadline, leaving the regional security landscape deeply unstable.