The Bab al-Mandab Strait, a 32km-wide (20-mile) waterway located between south-western Yemen and the Horn of Africa. It connects the Gulf of Aden with the Red Sea, which is linked to the Mediterranean by the Suez canal.

Soon after the start of the Gaza war in October 2023, the Houthis began attacking merchant vessels in the Red Sea and Gulf of Aden with missiles, drones and small boats, saying they were acting in support of the Palestinians.

Four ships were sunk, nine crew members were killed, and commercial traffic through Bab al-Mandab hit a record low as shipping companies rerouted their vessels around southern Africa.

Although the Houthis paused their attacks in response to the Gaza ceasefire last October, the number of transits through the strait has yet to return to previous levels, according to data from the International Monetary Fund.

In response to the situation in the Strait of Hormuz, Saudi Arabia has diverted more than 70% of its crude exports to the Red Sea port of Yanbu.

About 4 million barrels per day (bpd) have been shipped from there in recent weeks, compared with about 973,000 bpd a year earlier, according to data from Kpler and Signal Ocean.

Total petroleum volumes transiting Bab al-Mandab also rose to 7.4 million bpd in June, or about 7% of global output.

Mohammed Albasha of the US-based risk advisory firm Basha Report said it was not yet clear whether the Houthis would begin targeting vessels heading to Saudi Arabia.

“Even if no ships are attacked, the announcement alone is likely to disrupt shipping and create uncertainty for Saudi ports. Whether the Houthis move from threats to direct action remains the critical issue,” he told Reuters news agency.