"We are now witnessing a new phase in the war," Amir Mohammad Akraminia, the Iranian brigadier general, told state media on Thursday morning. Houthi militants claim to have bombed two Saudi oil tankers in the Red Sea, making good on their threat to blockade the Bab al-Mandab. The new squeeze on world oil supplies brings global energy markets closer to a tipping point. A crisis has been averted so far because China and the US are aggressively running through their stockpiles, easing the market pressure. Pete Hegseth, the war secretary, warned of "critical shortfalls" as he pleaded with congress to unlock more cash for a war that has already cost close to $38bn (£28bn).