The British military said a cargo ship on the new Omani UN-backed route sustained bridge damage from a projectile, hours after the IRGC warned that vessels without Iranian permission were transiting "illegally".

The stern warning underscores Tehran's resolve to retain control over the Strait of Hormuz and to resist transits that bypass its authorization.

The oil tankers, led by the Stoic Warrior vessel, sailed along the coast of the United Arab Emirates and then Oman on Thursday morning.

The UK Maritime Trade Operations (UKMTO) security agency reported that the incident occurred 7.5 nautical miles (14 kilometres) southeast of Dahit, in Oman's Musandam exclave.