Yemen’s Houthi movement said it attacked the Saudi-flagged oil tankers Encelia and Layla with missiles and drones overnight on Wednesday, in what it described as enforcement of a newly declared maritime blockade on Saudi Arabia. Saudi state media confirmed that the Encelia was struck while sailing in the Red Sea, causing a fire at the bow, though all crew were reported safe. The United Kingdom Maritime Trade Operations centre reported that an “unknown projectile” hit a tanker about 130 kilometres south-west of the Saudi coastal town of al-Shuqaiq, with no casualties. The attack on the Layla remained unconfirmed by independent sources.

President Donald Trump responded on Thursday by declaring that the United States would hold Iran responsible for any future Houthi strikes on shipping, calling the group a “Surrogate and/or Proxy of Iran,” and threatening “major military punishment” against both. The warning, posted on Truth Social, came hours after the US military completed a twelfth consecutive night of air strikes on Iranian military targets, including maritime assets and missile storage facilities. Trump had earlier threatened to destroy one Iranian bridge or power plant for each attack on vessels in the Strait of Hormuz.

The Houthi operation opens a new maritime front in the war that the United States and Israel launched against Iran in February. The group had announced a blockade of Saudi Red Sea ports on Monday, citing what it called an “unjust and oppressive siege” on Yemen and a recent Saudi missile strike on Sanaa airport. The Bab el-Mandeb strait, which the Houthis are now threatening, is a critical chokepoint through which around 12 per cent of global trade and a quarter of container traffic passes. Its disruption compounds the near-total closure of the Strait of Hormuz, where Iranian forces have effectively blocked traffic since March, forcing Saudi Arabia to redirect more than 70 per cent of its crude exports via pipeline to the Red Sea port of Yanbu.

The attacks pushed Brent crude above $100 a barrel for the first time since May, with prices rising more than 6 per cent on Thursday. Analysts note that a prolonged Houthi campaign could force tankers to avoid the Bab el-Mandeb entirely, adding weeks to voyages and sharply increasing freight and insurance costs. Ship-tracking data showed several tankers changing course in the Red Sea, and three vessels loaded with Saudi oil for China and India turned back on Tuesday. Two Chinese supertankers carrying a combined 4 million barrels of Saudi crude were still heading toward the strait on Thursday.

Diplomatic efforts to end the conflict show no sign of progress. US Secretary of State Marco Rubio said the price Iran pays “will get higher every night” until Tehran is ready for a deal it would honour, while Iranian officials dismissed the American approach as “illogical, excessively demanding and hegemonic.” The US military says its strikes aim to degrade Iran’s ability to threaten commercial shipping, and more than 50,000 American service members remain deployed across the Middle East on high alert.