Yemen's Houthi rebels sent an email to shipowners this week declaring that all vessels calling at Saudi Arabian ports, not only Saudi flagged ones, would be exposed to sanctions and could be targeted within the operational reach of the Yemeni armed forces. Bloomberg, which viewed the message, said it was the group's most explicit statement yet of the scope of a blockade they first threatened on Monday.
The Iran backed group framed the embargo as retaliation for what it calls Saudi Arabia's siege of Sanaa, the Yemeni capital. On the same day, an official aboard an oil tanker in the Red Sea told Bloomberg the crew had picked up a radio broadcast from Yemeni armed forces addressing shipping in the area and warning that Saudi vessels were blocked. The Saudi led coalition in Yemen said it had begun implementing operational measures to protect ships in the Bab el Mandeb Strait.
The move puts direct pressure on Yanbu, the Red Sea export hub that Riyadh has leaned on ever since the war with Iran choked traffic through the Strait of Hormuz to a near halt. Saudi Aramco has been diverting large volumes of crude across the east west pipeline from the Persian Gulf to Yanbu so that barrels can reach global buyers without transiting Hormuz. If shipowners take the Houthi threat at face value, that workaround narrows sharply.
It is not yet clear how effective the blockade will be in practice. The Houthis have not attacked a merchant vessel in months, and shipowners have been cautiously returning to Red Sea routings. But the emailed warning, delivered directly to commercial operators rather than broadcast on television, is designed to shift insurance premiums and charter decisions before a single missile flies.
For tanker owners, refiners, and P and I clubs, the immediate question is whether Yanbu loadings continue on schedule and whether war risk rates for Red Sea calls widen again. Saudi Arabia's Energy Ministry did not respond to a request for comment on the message.