Iran's Revolutionary Guard video showing its seizure of a Vietnamese vessel last year.
The United Kingdom Maritime Trade Operations (UKMTO) said late on Sunday it had received reports of an attack on a vessel near Yemen's port of Ras Isa and an investigation was being conducted.
In an advisory issued at 2150 GMT, the UKMTO - part of Britain's Royal Navy - advised mariners to exercise extreme caution in the area.
It put the vessel's position at approximately 23 nautical miles west of Ras Isa oil terminal on the Red Sea.
The last shipping incident near Ras Isa was in late 2019 when Yemen's Iran-aligned Houthi movement briefly seized a Saudi-flagged ship and two South Korean vessels.
Saudi Arabia is leading a military coalition that has been battling the Houthis for more than six years.
The alliance has accused the Houthis of attacking shipping in the Red Sea, one of the world's busiest maritime lanes leading up to the Suez Canal.
Similar incidents have taken place in the Persian Gulf region and the Arabian Sea. Iran has seized several vessels since 2019.