US Secretary of State Marco Rubio declared on Wednesday that Iran is “not serious about talks” to end the Gulf war, and warned that allowing Tehran to control the Strait of Hormuz would create a “very dangerous precedent” for global trade. His remarks, delivered at a meeting of Southeast Asian foreign ministers in Manila, came as the US military conducted an 11th consecutive night of strikes against Iranian targets and Yemen’s Iran-aligned Houthis threatened to attack any vessel loading or discharging Saudi oil, forcing at least seven tankers to reverse course in the Red Sea.

Speaking to ASEAN counterparts, Rubio said Washington remained “always committed to diplomacy” but accused Iran of failing to honour commitments made under a June interim ceasefire. “If they’re serious, we’re serious. If they’re not, then we will do what is necessary to protect our interests, and also the interests of our allies,” he stated. Iranian officials, for their part, told Reuters that mediators had presented a 10-day ceasefire proposal and that Interior Minister Eskandar Momeni had visited Pakistan to request continued mediation. Analysts at the London-based Chatham House assessed that the Houthi naval threats were a tactical move by Tehran “to create leverage for a negotiation.”

The disruption has tightened two of the world’s most critical energy chokepoints simultaneously. With Iran already restricting traffic through Hormuz—through which roughly 20% of global oil and LNG transits—the Red Sea route via the Suez Canal had become the main alternative for Saudi crude exports to Asia. Brent crude rose to near six-week highs above $91 a barrel, and US gasoline prices climbed back over $4 a gallon. ASEAN foreign ministers, in a joint statement, expressed “serious concern” that the conflict was undermining mediation efforts and noted that the region depends on the Strait of Hormuz for up to 60% of its energy supplies.

Rubio explicitly linked the Hormuz standoff to freedom of navigation disputes in the South China Sea, telling the ministers that a precedent of a state controlling an international waterway by force “will repeat itself in other parts of the world, including in this region.” He later met with fellow Quad members—Australia, India and Japan—to reaffirm maritime security cooperation, and was scheduled to hold bilateral talks with Chinese Foreign Minister Wang Yi, with a possible US-China leaders’ summit on the agenda. The 60-day negotiating window established by a June 17 memorandum of understanding has now passed its halfway point, with no diplomatic breakthrough in sight and US Central Command stating its strikes aim to “degrade” Iran’s ability to threaten commercial shipping.