Houthis Threaten Second Maritime Front as U.S.–Iran War Spreads Toward the Red Sea

A declared blockade against Saudi ports is already diverting tankers and threatening the main alternative to the Strait of Hormuz.

Yemen’s Iran-aligned Houthi movement is threatening to open a second maritime front in the U.S.–Iran war, declaring what it describes as a naval blockade against Saudi Arabia and warning commercial shipping companies to avoid Saudi ports.

The threat is already affecting vessel movements. Tankers carrying Saudi crude have reversed course rather than pass through the Bab el-Mandeb Strait, raising concerns that the conflict could now disrupt both of the region’s most important maritime chokepoints at the same time.

With traffic through the Strait of Hormuz already severely reduced, the Red Sea has become increasingly important as an alternative outlet for Gulf energy exports. A sustained Houthi campaign against Saudi-linked shipping could place that fallback route at risk and sharply increase the war’s impact on global energy supplies.

Houthis Declare a Blockade Against Saudi Arabia

The Houthis announced that a naval blockade against Saudi Arabia had taken effect, expanding their maritime threats beyond vessels directly linked to Israel.

According to a July 20 email reviewed by Reuters, the Houthi-run Humanitarian Operations Coordination Center warned shipping companies against loading or discharging cargo at Saudi ports. The message said vessels that ignored the directive could face sanctions and potential targeting, including after leaving the immediate Red Sea region.

The warning effectively attempts to force commercial operators to choose between continuing business with Saudi Arabia and risking Houthi attack.

Unlike earlier Houthi restrictions that were publicly framed around Israel and the war in Gaza, the latest declaration directly targets Saudi maritime trade. That makes it a significant expansion of the group’s campaign and ties the Red Sea more closely to the widening U.S.–Iran conflict.

Tankers Are Already Changing Course

The threat has not remained purely rhetorical.

At least two tankers carrying Saudi crude toward customers in China and India reversed course near the Bab el-Mandeb Strait after the Houthi warning. The vessels instead moved north toward the Suez Canal, avoiding the Yemeni coastline and the southern Red Sea chokepoint.

Additional reporting indicates that as many as four Saudi-linked tankers altered their routes following the declaration. Several had loaded crude at the Saudi Red Sea port of Yanbu, while another reportedly turned away before completing its planned loading operation.

The diversions do not prove that the Houthis can completely close Bab el-Mandeb. They do show, however, that a credible threat may be enough to disrupt traffic without the group firing a missile or launching a drone.

Commercial shipping decisions are driven by risk, insurance availability, crew safety, and the possibility of losing a high-value vessel. Once operators believe a route has become an active combat zone, traffic can collapse even when the waterway remains physically passable.

Bab el-Mandeb Has Become More Important Because of Hormuz

The timing of the Houthi declaration makes the threat especially serious.

The Strait of Hormuz, the main maritime outlet for Gulf oil and liquefied natural gas, is already operating at a fraction of its normal commercial capacity because of the U.S.–Iran war. Iranian attacks, naval warnings, mines, and continuing U.S. strikes have driven many major tanker operators away from the route.

Saudi Arabia has therefore relied more heavily on its east–west pipeline network, which carries crude from production areas near the Persian Gulf to the Red Sea port of Yanbu. Oil loaded at Yanbu can travel north through the Red Sea and the Suez Canal or south through Bab el-Mandeb toward Asian markets.

That system provides Saudi Arabia with a partial way around Hormuz. The Houthi blockade threat now places pressure on the alternative route as well.

Approximately 7.4 million barrels of petroleum products per day moved through Bab el-Mandeb in June, according to shipping data cited by Reuters. That amounted to roughly 7% of global oil output and was substantially higher than the volume recorded a year earlier.

The increase reflects the route’s growing importance during the Hormuz crisis. It also explains why the possibility of renewed Houthi attacks is receiving such close attention from energy markets.

Iran Reportedly Prepared the Houthi Option in Advance

The threat did not emerge without warning.

Reuters reported on July 16 that Iran had instructed the Houthis to prepare to close the Red Sea gateway if the United States attacked Iran’s electrical power network. A source close to the group said missiles and drones had been positioned near Bab el-Mandeb and in areas overlooking Hodeidah and the Gulf of Aden.

Those reports suggest that the Red Sea front has been developed as an escalation option rather than as an improvised response.

Iran can use the Houthis to increase pressure on U.S. allies and global shipping without relying solely on its own forces in the Persian Gulf. This creates another layer of escalation and complicates any attempt to contain the war geographically.

Iran has already sought to impose costs through Hormuz. A Houthi campaign around Bab el-Mandeb could extend that pressure to Saudi Arabia, Egypt, Red Sea shipping, and vessels using the Suez Canal.

A Two-Chokepoint Crisis Could Reshape the Energy War

The strategic danger is not necessarily the total closure of either waterway. It is the possibility that both become sufficiently hazardous that normal commercial operations are no longer viable.

Hormuz and Bab el-Mandeb serve different routes, but together they shape the movement of a large share of Middle Eastern energy exports.

Hormuz connects Persian Gulf producers with the Arabian Sea. Bab el-Mandeb connects the Red Sea and Suez Canal with the Gulf of Aden and Indian Ocean.

If Hormuz remains heavily disrupted while Saudi-linked traffic is threatened in Bab el-Mandeb, exporters may be forced into longer and more expensive routes around Africa. Some cargoes could also be delayed at ports or moved through pipelines with limited spare capacity.

Reuters reported that Asian refiners are already examining longer routes through the Suez system and around the region to maintain access to Saudi crude.

These workarounds could prevent a complete supply cutoff, but they add transit time, freight costs, insurance expenses, and pressure on available tankers.

The Houthis Have Disrupted Global Shipping Before

The latest threat is credible because the Houthis have previously demonstrated an ability to disrupt commercial traffic across the Red Sea.

Beginning in late 2023, the group launched missiles, drones, and boarding operations against ships it claimed were connected to Israel or its allies. Many shipping companies responded by avoiding the Red Sea and sending vessels around the Cape of Good Hope.

Those attacks declined following the October 2025 Gaza ceasefire, allowing more traffic to return. The military infrastructure and operational experience behind the earlier campaign, however, did not disappear.

The current declaration therefore comes from an organization with a documented record of striking merchant vessels and forcing major international carriers to alter their routes.

The group does not need to control Bab el-Mandeb in the traditional naval sense. It needs only to create enough danger that shipowners, insurers, and crews refuse to enter.

Saudi Arabia Rejects the Blockade

Saudi Arabia has rejected the Houthi declaration and said it will take the necessary measures to protect its maritime interests.

Saudi Aramco has continued loading crude at Yanbu, although some vessels have reportedly taken additional precautions, including reducing or disabling public tracking signals.

The continuation of loading operations suggests Riyadh is not accepting the blockade as effective or legitimate. However, the course changes by several tankers show that commercial operators may respond more cautiously than the Saudi government.

This creates a familiar maritime-security problem: a government may insist that a route remains open, but shipping companies ultimately decide whether their ships and crews will enter it.

The United States Faces a Wider Maritime Problem

The Houthi declaration places additional pressure on Washington.

The United States is already conducting sustained military operations against Iran while attempting to preserve commercial passage through Hormuz. A new Red Sea campaign could force the U.S. and its partners to divide intelligence, air-defense, naval escort, and strike resources across two separate maritime theaters.

President Donald Trump has warned against efforts to block Red Sea access, signaling that Houthi attacks could provoke an American response.

The United States and its allies have previously intercepted Houthi missiles and drones and carried out strikes against launch sites in Yemen. Returning to that campaign while the U.S. is actively striking Iran would represent a substantial geographic expansion of the war.

It would also raise the risk of direct conflict involving Saudi Arabia, Yemen, Iran, the United States, and additional naval powers dependent on Red Sea trade.

A Blockade in Name, but a Real Economic Threat

The Houthi declaration should not yet be treated as proof that Bab el-Mandeb has been closed.

Shipping is still moving, Saudi ports remain operational, and the Houthis have not demonstrated complete control over the waterway. The term “blockade” reflects the group’s declaration and intended policy, not necessarily an internationally recognized or fully enforceable naval closure.

But the economic threat is already real.

Tankers have altered course, refiners are considering alternative routes, and energy markets are reacting to the possibility that Red Sea traffic could face the same kind of disruption already affecting Hormuz.

The immediate danger is therefore not that every ship will suddenly be stopped. It is that repeated threats or even a small number of attacks could persuade much of the commercial fleet to stay away.

The War Is Expanding Beyond Hormuz

Until now, the central maritime front of the U.S.–Iran war has been the Strait of Hormuz. The Houthis are now threatening to broaden that conflict into the Red Sea and place Saudi Arabia’s alternative export route under pressure.

That creates the possibility of a coordinated maritime squeeze: Iranian forces contesting passage through Hormuz while an Iran-aligned armed group threatens ships using Bab el-Mandeb and Saudi Red Sea ports.

Whether the Houthis carry out sustained attacks remains uncertain. But the tanker diversions show that the threat alone is already changing commercial behavior.

The war has not yet closed both chokepoints. It has, however, created a situation in which neither can be assumed to remain safe.