Yemen's Houthi movement will widen its naval blockade of Saudi Arabia from Jizan to the ports of Jeddah and Yanbu, Mohammad Taher Anaam, adviser to the chairman of the Supreme Political Council, told Lebanese Al Mayadeen on July 23.

Extending the blockade to Yanbu would strike directly at the workaround Riyadh has used since Iran closed the Strait of Hormuz in February, when the kingdom began diverting millions of barrels a day through its East-West Pipeline to the Red Sea terminal. Yanbu shipments have averaged 4mn barrels a day in recent weeks, against about 973,000 b/d a year earlier.

Anaam said the movement's demand was the lifting of the blockade on Yemen and that attacks on Saudi Arabia would continue until that was achieved. He said the campaign had begun in the Jizan area and would expand to Jeddah, Yanbu and the Yanbu economic zone.

He warned that Sanaa would not hesitate to target any country cooperating with Saudi Arabia, and said any future negotiation or mediation would proceed under continued attacks on the principle of "blockade for blockade".

Anaam said Yemeni forces would respond to any US action by targeting American ships and interests, and that Yemeni missiles could reach those targets. He described Yemen's missile and intelligence capabilities as significantly improved and its forces as fully prepared.

The comments followed a threat by US President Donald Trump of "major military punishment" against Iran and the Houthis if attacks on shipping continued. Trump said he would hold Tehran responsible, describing the Yemeni group as a surrogate or proxy of Iran.

The Houthis claimed missile and drone strikes on the Saudi tankers Encelia and Layla in the Red Sea earlier on July 23, sending Brent crude above $100 a barrel for the first time since May 26.