Iran’s military central command warned that any major new attack by the United States and its allies would trigger sustained retaliation against U.S. bases and interests, treating Washington’s regional allies as parties to the conflict. The warning followed a U.S. State Department alert about unforeseen escalation, possible flight cancellations and airspace closures, while Houthi claims of missile and drone strikes on Riyadh and an oil facility in Yanbu unsettled Gulf markets. Saudi Arabia’s benchmark index fell 0.3% to 10,750, all Gulf bourses closed lower, and investors focused on possible de-escalation signals from U.S. President Donald Trump’s meeting with Gulf leaders. Iran said it would keep most shipping blocked through the Strait of Hormuz until the June interim ceasefire’s terms were met as Tehran interpreted them, after the agreement collapsed in July.