Iran-US Ceasefire Collapses as Strait of Hormuz Tensions Flare

The ceasefire that ended the 2026 Iran war has effectively collapsed, with the United States and Iran trading strikes over control of the Strait of Hormuz just weeks after signing the Islamabad Memorandum. President Trump declared the truce “over” this month, even as American and Iranian officials scrambled to salvage talks in Muscat, Oman. Oil markets have reacted sharply, and shipping through the strait has slowed to a fraction of its normal volume.

What to know:

• The Islamabad Memorandum is unraveling. Signed June 17 by the US and Iranian presidents, the 60-day framework ended a US naval blockade, reopened the Strait of Hormuz, and offered Iran a broad oil-sanctions waiver, but vague language on safe passage became the flashpoint that broke it.
• Iran struck multiple commercial vessels within days. The Qatari-owned LNG tanker Al Rekayat and the Saudi-flagged supertanker Wedyan were both hit by projectiles on July 7; Al Rekayat was evacuated after an engine-room fire, and a third ship was targeted less than 24 hours later.
• Oil prices spiked. Brent crude rose as much as 4 percent to nearly $79 a barrel and US benchmark crude climbed a similar amount, as traders priced in the risk of a prolonged disruption to one of the world’s busiest oil corridors.
• Strait traffic has cratered. Maritime tracker Windward recorded just six vessel crossings in a single 12-hour window last week, down from 18 to 22 crossings a day earlier in the month.
• Diplomacy hasn’t stopped. Iranian Foreign Minister Abbas Araghchi met Omani counterpart Badr bin Hamad Al Busaidi in Muscat, while a US team led by Vice President JD Vance, Secretary of State Marco Rubio, envoy Steve Witkoff and Jared Kushner also engaged mediators over the weekend.

The truce’s central flaw was baked into its own text. The Islamabad Memorandum required only that Iran use “its best efforts” to ensure safe passage through the Strait of Hormuz, free of charge, for 60 days, language Tehran has since read as license to impose “service fees” once that window closes and, critics argue, as cover for asserting a broader claim over the waterway. When Iranian forces began striking commercial shipping rather than merely threatening it, Washington concluded the memorandum was dead in all but name, revoking an earlier authorization tied to Iranian oil sales and launching fresh strikes on Iranian positions.

Trump made that judgment explicit at the NATO summit, telling reporters the ceasefire was “over” and dismissing Iranian officials as “scum” and “sick people,” even as he confirmed Washington would keep talking. The advocacy group United Against Nuclear Iran has catalogued what it calls multiple Iranian breaches of the memorandum, spanning the use of force, the pace of negotiations, freedom of navigation and cooperation on nuclear issues. Iran’s foreign ministry disputes the framing, denying it requested any new round of talks and saying it merely agreed to receive a Qatari delegation trying to broker a path through the impasse.

The fallout is landing hardest on Gulf states that had no stake in the underlying dispute. Formula 1 canceled its Bahrain and Saudi Arabian Grands Prix back in March after Iranian retaliatory strikes landed within range of both circuits, and organizers have since built contingency plans around a shortened season rather than reschedule the lost races. Saudi Arabia has stressed that it neither sought nor joined the fight, even as it now manages the economic and security consequences of a conflict unfolding largely at its doorstep.

What distinguishes this round of escalation from the acute war-fighting phase earlier in the year is where the pressure point has moved, from population centers and military installations to the tanker lanes themselves. Iran’s naval forces have at points declared the strait closed outright, even as vessel traffic on the Omani side continued at reduced volume, underscoring how fragmented control over the passage has become between Iranian claims and the practical reality of who can still move a ship through safely.

The Oman-hosted talks are now aimed less at resolving the broader dispute than at designing some kind of interim management mechanism for the strait itself, covering insurance, escort protocols and fee structures for the vessels still willing to attempt the crossing. Iran, for its part, points to a separate grievance: continued Israeli operations against Hezbollah in southern Lebanon, which Tehran characterizes as a US commitment left unenforced. Untangling those threads, mediators concede, may take longer than the 60 days the original memorandum allotted.

For now, the practical measure of whether diplomacy is working will not be a signing ceremony but something more mundane: how many tankers are willing to cross the strait on a given night, and at what price insurers are willing to cover them.