Yemen’s Houthi movement announced a naval blockade against Saudi Arabia on 20 July, and within 24 hours at least two tankers carrying Saudi crude to Asia reversed course in the Red Sea. The vessels Rodos and Xin Long Yang, loaded with roughly 700,000 and 2 million barrels respectively, turned back from the Bab el-Mandeb Strait and headed north toward the Suez Canal, according to shipping data cited by multiple agencies. A third tanker, New Prime, aborted its approach to the Saudi Red Sea port of Yanbu before entering the strait. The Houthi military spokesman, Yahya Saree, described the measure as an “eye for an eye” response to what the group calls a prolonged Saudi siege of Yemen, and warned that any vessel loading or unloading at Saudi ports could become a target “in any location.”

Saudi Arabia’s foreign ministry rejected the Houthi accusations as baseless and said the kingdom would take “all necessary measures” to protect its ships. The spokesman for the Saudi-led military coalition, Turki al-Malki, stated that threats against transiting vessels would be met with “firmness and force.” From Washington, President Donald Trump said the United States would “take care of” the Houthis if a blockade materialised, recalling previous US operations against the group. Viewed from Tehran, the Houthi move aligns with Iran’s declared strategy of widening the economic cost of the conflict; Iranian officials had earlier pressed the Houthis to close Bab el-Mandeb if US strikes on Iranian infrastructure continued, according to regional security sources. The internationally recognised Yemeni government, backed by Riyadh, signalled readiness to intensify operations against the Houthis.

The immediate consequence is the disruption of the main alternative export route for Saudi crude. Since the effective closure of the Strait of Hormuz by Iran, Saudi Arabia has relied on its Red Sea terminal at Yanbu to ship roughly 4 million barrels per day, mostly to Asian buyers. A full closure of Bab el-Mandeb could remove about 7 percent of global oil supply from the market, compounding the roughly 10 percent already lost through the Gulf, according to Kpler data. Oil prices rose more than 2 percent on 21 July, with Brent crude hovering above $91 per barrel. Shipping insurers have raised war-risk premiums, and maritime security firms are advising operators to reassess Red Sea transits after calling at Saudi ports. The diversions force vessels onto far longer routes around the Cape of Good Hope, adding weeks of voyage time and higher freight costs.

The blockade threat follows a rapid unravelling of the informal truce that had held in Yemen since 2022. The trigger was a Saudi-led coalition strike on Sanaa airport on 13 July, aimed at preventing an Iranian aircraft carrying a Houthi delegation from landing after the funeral of Iran’s supreme leader. The Houthis retaliated with missile and drone attacks on Saudi Arabia’s Abha airport, the first direct cross-border strike since 2022. Analysts in European capitals note that the Houthis, while maintaining a degree of operational autonomy, are acting in close coordination with Tehran’s broader effort to pressure Washington by threatening both Hormuz and Bab el-Mandeb simultaneously. The group controls territory within 100 kilometres of the strait and has previously demonstrated the ability to disrupt commercial shipping with mines, drones, and boarding teams.

Diplomatic channels remain active but fragile. Pakistani and Qatari mediators have presented Tehran with a ten-day ceasefire proposal, and Iranian officials confirm receiving de-escalation plans, though no details have been made public. The US State Department has not committed to new negotiations, with Secretary of State Marco Rubio conditioning talks on a change in Iranian behaviour. The Saudi-led coalition says it has begun implementing measures to protect vessels transiting Bab el-Mandeb, while the Houthis have not yet specified how the blockade will be enforced. Shipping data indicates that Yanbu port continues to operate for vessels already inside the Red Sea, but the rerouting of laden tankers signals that the threat is already reshaping maritime traffic before any military enforcement begins.