Key development: The US has threatened to ground Iranian airlines worldwide starting Wednesday — any airport or company that services them would be cut off from the dollar system.

Economy

(Update) The US says it’ll ground Iranian airlines worldwide starting Wednesday — service them and you risk being cut off from the dollar. That’s a major escalation: it forces every country to pick between doing business with Iran’s carriers or the US financial system. (Al Jazeera, The Hindu)

Context: Treasury Secretary Scott Bessent had already vowed “economic D-Day” on Iran. Today he put a date on it: September 23. The move targets Iran’s airlines worldwide, potentially forcing them out of international operations by cutting off airports and service companies from the US financial system. Tehran’s leaders, who have weathered past sanctions, are betting otherwise.

Sources: Al Jazeera | The Hindu | BBC

Military Operations

(Update) Two tankers got hit in the Strait of Hormuz by an “unknown projectile” or debris, and at least two crew members are hurt. Hormuz is the world’s most important chokepoint for crude, so attacks here carry direct oil-market risk. (France 24, Middle East Eye)

Context: UKMTO reported the attacks Monday; a separate UKMTO alert cited by Middle East Eye says an LPG tanker hit by debris reported all crew safe. The attacks follow the September 15 incident involving the tanker El Gaia — Tehran says it hit mines, while Washington says it was struck by a missile and then a drone — making this the latest in a series of incidents in the strait.

Sources: France 24 | Middle East Eye | BBC

Diplomacy

Pakistan’s interior minister landed in Tehran for talks amid looming fears of a renewed US-Iran war. Islamabad has in the past tried to broker dialogue between Tehran and Washington. (Middle East Eye)

Context: The visit comes amid heightened tensions and the collapse of earlier negotiations. Pakistan shares a border with Iran and has in the past tried to broker dialogue between Tehran and Washington; Naqvi has visited Tehran several times since that mediation effort began.

Sources: Middle East Eye

What to watch: Whether countries actually comply with the Wednesday airline deadline — and whether Tehran responds with further escalation in the strait.