Houthis take Greater and Lesser Hanish after the garrison leaves for Djibouti

Yemen's Houthi movement took the Greater and Lesser Hanish islands in the southern Red Sea after hundreds of government-allied troops left the archipelago, according to two Yemeni government officials and one Houthi official who spoke to the Associated Press on Monday. The islands sit about 160 kilometres north of the Bab el-Mandeb Strait, the narrow gate between the Red Sea and the Gulf of Aden.

The takeover follows last week's capture of the Red Sea port of Mokha and of Mayun, also called Perim, which splits the strait into two shipping lanes. Yemen Shabab TV reported on Sunday that nearly 1,000 government-aligned soldiers who had been stationed on the Hanish group and on Zuqar Island arrived in Djibouti after a Houthi assault. It is not public exactly when the last government unit left Greater Hanish.

The Hanish islands had been held by the United Arab Emirates and its southern Yemeni allies. Their fall puts Houthi positions about 32 kilometres from Camp Lemonnier, the main United States military base in Africa, on the Djibouti side of the strait. China, France and Japan also keep bases in Djibouti. None of those governments confirmed a change in force posture on Monday.

The geography is the point. Iran closed, or at least tightly rationed, the Strait of Hormuz in the opening days of the war that began with United States and Israeli strikes on 28 February. In peacetime about a fifth of the world's traded oil and gas moves through Hormuz. Saudi Arabia has since pushed more crude toward Red Sea terminals and out through Bab el-Mandeb. That alternative now sits under a movement that already fires at Saudi infrastructure and at ships.

Houthi officials said they occupied the two islands as Saudi-backed government forces tried to claw back ground around the strait. Fighting intensified on Sunday. Government units attacked along the Red Sea coast. Houthis fired into Saudi Arabia. One Yemeni government official called the loss of Mokha and Mayun a painful defeat and said more troops would be sent to the coast. The internationally recognised government in Aden also banned the entry and circulation of Iranian goods, according to the state-run Saba news agency, after a meeting chaired by Central Bank of Yemen Governor Ahmed Ghaleb.

China said on Monday it was deeply concerned about further Houthi attacks on Saudi Arabia and called strikes on Saudi energy infrastructure unacceptable. Beijing is a large buyer of Gulf crude and has little interest in a second closed chokepoint. Brent has already traded above $108 a barrel in recent days on fears that diesel and other products will stay tight.

The 2022 truce in Yemen had largely held until this year. That pause is gone. The Houthi advance toward Marib and Taiz continues on the mainland, according to reporting from Al Jazeera and AP. Gulf states cancelled planned talks with Iran after Houthi ballistic missile attacks on Saudi Arabia and on Yemeni government forces. The Red Sea campaign and the Hormuz file are now one problem with two gates.

Mayun sits inside the strait. Greater Hanish is a 20-kilometre volcanic island with lava flows that reach both coasts. Lesser Hanish and Suyul Hanish lie on the same north-east to south-west line. Control of that chain gives a force with drones and anti-ship missiles a set of platforms from which to watch, and if it chooses to fire on, traffic moving north toward Suez or south toward the Arabian Sea.

Insurers and shipowners already price Red Sea risk. The new facts are the withdrawal of the garrison, the arrival of those soldiers in Djibouti, and the confirmation from both sides that Houthi units are on Greater and Lesser Hanish. The government has promised reinforcements. It has not said from where, or on what timetable, those units will arrive.

Saudi Arabia's East-West Pipeline, a seven-million-barrel-a-day line that lets crude bypass Hormuz on the way to Red Sea terminals, was hit by drones launched from Iraq in the days before the island seizure. That line was shut. The combination is simple to state and hard to reverse: Hormuz constrained, the pipeline damaged, Bab el-Mandeb now flanked by Houthi-held islands.

What happens next depends on whether Riyadh and its Yemeni allies try to retake Mayun and the Hanish group, and on whether Iran treats the new shoreline as leverage in any later talk about shipping fees and permits in the Gulf. For now the islands have changed hands, the soldiers who held them are in Djibouti, and the strait that was supposed to replace Hormuz is no longer a quiet alternative.