After several of Iran’s most important allies suffered major losses in the wars that followed Hamas’ October 7, 2023, attack on Israel, regional officials and experts say Tehran has increasingly relied on the Houthis and Iraqi militias to pressure Saudi Arabia and other US allies in the Gulf.

In July, Saudi Arabia and the US struck Iran-backed Iraqi militias after the groups were blamed for drone attacks on Saudi oil facilities claimed by the Houthis.

Houthis seize strategic port

The immediate threat is now concentrated on Yemen’s Red Sea coast. Four Yemeni government military sources told Reuters on Thursday that the Houthis had seized Mocha, a historic port city about 80 km from the Bab el-Mandeb Strait.

The Associated Press reported that two residents said Houthi forces had entered and spread across the city, although it could not independently verify their accounts.

The Houthis have also advanced towards the strategic Hanish Islands, according to Yemeni government sources, while government forces and their allies are moving south towards Dhubab. The town sits directly on the Bab el-Mandeb Strait, opposite the island of Perim.

Control of Dhubab and Perim would give either side a crucial position from which to influence traffic through the Bab el-Mandeb Strait.

Key shipping route at risk

Bab el-Mandeb links the Red Sea with the Gulf of Aden and is a critical route for ships carrying oil, fuel and other goods between Asia, Europe and the Middle East via the Suez Canal.

Its importance has increased as the conflict with Iran has severely disrupted shipping through the Strait of Hormuz, a key route for Gulf oil exports.

Saudi Arabia has been sending more oil through the Red Sea as an alternative to the disrupted Strait of Hormuz. But the alternative route is now also coming under pressure from the Houthis.

The Houthis have attacked Saudi oil facilities and shipping in the Red Sea and declared a naval blockade against Saudi shipping.

Yemen risks return to full-scale civil war

The fighting also raises the risk of Yemen returning to full-scale civil war.

A UN-brokered truce in 2022 largely stopped years of major fighting between the Houthis and forces supporting Yemen’s internationally recognised government. Recent clashes are now threatening that fragile calm.

More than 20,000 people have been displaced by fighting in Taiz and Hodeida over the past two weeks, according to Yemeni government data cited by Reuters. Hundreds of women and children also left Mocha on Thursday.

Saudi Arabia says recent Houthi attacks on civilian and economic sites in its south have wounded 73 people, including women and children.

The Houthis, meanwhile, said Saudi strikes hit several provinces in Yemen. Saudi Arabia has not confirmed those strikes.

Saudi warning sent to Iran

Saudi, Pakistani and Iranian sources told Reuters that Pakistan conveyed a Saudi warning to Tehran asking it to rein in the Houthis.

A senior Iranian official told Reuters that Tehran does not control the Houthis. Two other Iranian sources, however, told the news agency that Tehran had instructed the Houthis to attack Saudi Arabia and promised additional funding and weapons.

The Houthi advance towards Bab el-Mandeb therefore adds another danger to the regional conflict: Yemen risks sliding back into full-scale war while another major route for global oil and trade comes under growing pressure.