An oil tanker was seized by the Iranian navy in the waters between Iran and Oman on Thursday, according to state media.

Iran’s state-run news agency IRNA published a brief story confirming the seizure by the navy but did not identify the vessel.

Earlier Thursday, the United Kingdom Maritime Trade Operations, or UKMTO, said it had received a report of several gunmen boarding a ship in the Gulf of Oman.

Four to five “unauthorized” individuals who were “armed” and “wearing military style black uniforms with black masks” reportedly boarded the vessel early Thursday in an area some 50 nautical miles east of Sohar, a port city on Oman’s northern coast, according to a notice from the UKMTO, which is part of Britain’s Royal Navy and provides warnings to sailors in the Middle East.