Four Tankers Afire in Strait of Hormuz as IRGC Cites 'Unauthorised Routes'

Four oil tankers have caught fire and exploded in the Strait of Hormuz, Iran's Revolutionary Guards Navy said on Friday, October 30, in the most serious escalation yet for the waterway that carries roughly one-fifth of global oil supplies.

The IRGC Navy accused the vessels of using what it called unauthorised routes, according to Iranian state media. In its latest statement, the force said a fourth tanker, loaded with more than 2 million barrels of crude oil, struck a mine, suffered a powerful explosion and was burning. An earlier IRGC statement said another of the tankers, also carrying 2 million barrels of crude, had hit a naval mine.

Reuters could not immediately verify either claim. No nationalities, operators or flag states of the four vessels were disclosed — a gap that will complicate war-risk underwriting decisions for tonnage still in the Gulf.

What do independent reports say?

The United Kingdom Maritime Trade Operations agency separately reported an incident in the Strait of Hormuz. A verified source told UKMTO that a crude oil tanker was struck by an unknown projectile while completing an outbound transit of the waterway.

In an earlier advisory, UKMTO said a vessel was hit by an unknown projectile on its port side roughly 40 nautical miles — about 74 km — south of Iran's Lavan Island, an island in the Gulf off Iran's southern coast. The strike caused a fire on board. The crew were reported safe, and there was no reported environmental impact.

Whether the UKMTO-referenced vessels are among the four tankers named by the IRGC remained unclear at the time of reporting. For charterers and owners, that ambiguity matters: two data streams, one from the perpetrator and one from a monitoring agency, cannot yet be reconciled into a single casualty count.

Drone claims and US denials

Iranian state media also said Iranian forces downed and captured an MQM-170 US drone over Qeshm Island, near the Strait of Hormuz, and that Iran destroyed an unmanned US vessel in the eastern strait.

The US military's Central Command flatly denied the second claim. "All U.S. military unmanned surface vessels in the Middle East are accounted for, including a squadron of advanced sea drones on patrol in the Strait of Hormuz," CENTCOM said in a statement on X. There was no immediate US reaction to the drone-capture claim, and Reuters could not independently verify either report.

What is the context for shipping?

Tensions in the strait have persisted since the US-Israeli strikes on Iran at the end of February. The waterway's stakes are hard to overstate: approximately 20 percent of the world's oil supply transits it, meaning even partial disruption propagates quickly into freight rates, insurance premia and crude differentials far beyond the Gulf.

For tanker owners, the immediate commercial question is routing. Mine strikes on laden vessels — two cargoes of roughly 2 million barrels each, if the IRGC figures hold — represent a step change from the harassment and projectile attacks seen earlier in the escalation. For refiners and traders, the reports raise the prospect that outbound transits, until now the safer leg, are exposed too.

There is precedent for diplomacy, though no evidence it is advancing. On October 18, Iranian Foreign Minister Abbas Araqchi told Iranian media that Iran's offer to the United States to reopen the Strait of Hormuz within seven days remains on the table — a proposal that, notably, presumes Iranian control over the closure itself.

The backdrop also includes direct US-Iranian kinetic exchanges: on October 6, US forces destroyed an Iranian-affiliated dhow in the Gulf of Oman after determining it was conducting surveillance and helping target American warships.

What comes next?

With casualty claims unverified, vessel identities undisclosed and both sides trading denials over drones, the immediate trajectory points toward higher war-risk premiums and more cautious transits through a chokepoint that the world's oil market cannot route around quickly. Whether Iran's seven-day reopening offer resurfaces as a negotiating instrument — or disappears under fresh minefield reports — will define the risk picture for Gulf shipping in the weeks ahead.