TEHRAN: Iran's Revolutionary Guards said on Friday (Sep 18) they struck an oil tanker in the Strait of Hormuz, according to state news agency IRNA, as a British maritime agency also reported an attack.

Iran has maintained its stranglehold on the strategic strait as Washington continues pressing its counterblockade of Iranian ports during the Middle East war.

The Islamic Republic wants to charge ships for passage, attacking vessels it accuses of attempting to circumvent its preferred route.

"The Togo-flagged oil tanker Trend had been targeted and detained after a fire broke out on board" late on Thursday, the statement said, calling it an attempted "illegal passage".

Early on Friday, the United Kingdom Maritime Trade Operations (UKMTO) said a ship was hit by an "unknown projectile", causing a fire that was extinguished.

The monitoring agency had also reported a "security incident" in Hormuz late on Thursday, without giving details. 

It was unclear if the IRGC and UKMTO reports referred to the same incident.