Multiple vessels operating the Mideast Gulf have received radio transmissions stating that the strait of Hormuz has been closed, the UK Maritime Trade Operations agency said today.

The UKMTO said broadcasts or statements indicating a closure are not legally binding and it advised vessels to transit with caution. The reports from vessels were not independently verified, UKMTO said.

An unverified transmission shared with Argus stated: “From now on the strait of Hormuz is banned for all ships… No ship [of any type] is not allowed to pass [through] the strait of Hormuz.” The message was said to be broadcast from the Iranian-flagged Bahram 1, whose location was last shared in 2024.

The strait of Hormuz is international water, overlapped by the territories of Iran and Oman. While coastal state sovereignty exists in territorial waters, it cannot be used to bar passage of ships.

The US military today begun “major combat operations” in Iran following co-ordinated Israeli strikes, marking the most significant escalation in years in the oil-rich Mideast Gulf region and sharply raising the risk of oil and gas supply disruptions.

Marine traffic through the Gulf remains high, ship tracking platforms show, although a handful of laden and ballast tankers operating in the area, mostly bound for Asia-Pacific destinations, have performed U-turns.

Source: Argus by Melissa Gurusinghe and Andrey Telegin