On the sidelines of a NATO summit on Wednesday, Donald Trump made a warning that erased weeks of fragile diplomacy in a single sentence. "We hit them very hard last night," the US president said, before threatening to strike Iran's electric plants, desalination facilities and Kharg Island — the oil-export hub through which a substantial share of Iran's crude passes — again that evening. Hours later, US Central Command confirmed that fresh strikes were already under way, stating that their purpose was to degrade Iran's ability to threaten freedom of navigation in the Strait of Hormuz. The collapse followed Trump's declaration that an interim deal, brokered by Pakistan and enshrined in the Islamabad Memorandum of Understanding, was finished.

Pakistan's Foreign Office responded by urging all parties to "uphold their respective commitments" under that agreement — a careful form of words that implicitly blamed at least one side for the breakdown without naming it. UN Secretary-General António Guterres added his voice, calling for "maximum restraint" and an immediate return to talks, reflecting a wider international anxiety that the conflict could rapidly spiral beyond its current boundaries. Tehran's reaction sharpened those fears considerably. Iranian state broadcaster PressTV, citing unnamed government officials, reported that Iran had threatened to close the Strait of Hormuz entirely if US strikes continued — and to retaliate against what it called "enemy targets" at a ratio of two strikes for every one it received.

Earlier closures of the strait this year had already sent shockwaves through global energy markets, given that the waterway carries a critical portion of the world's seaborne oil. Whether Washington's stated goal — limiting Iranian naval power in the Gulf — can be achieved through air strikes alone, or whether it will instead harden Tehran's resolve to shut the strait completely, is a question that oil traders, shipping companies and neighbouring governments are now asking with considerable urgency.