A group of armed boats tried to seize a vessel 16 nautical miles (29.6 km) north of Oman, the UK Maritime Trade Operations said on Tuesday, quoted by "Reuters".
UKMTO said it was investigating the incident, which occurred while separating incoming traffic in the Strait of Hormuz.
Numerous small armed vessels tried to contact the ship via VHF radio, but it ignored requests to stop and continued on its planned route, the agency said.
The strait connects the Persian Gulf with the Gulf of Oman and the Arabian Sea beyond it.
OPEC members Saudi Arabia, Iran, the United Arab Emirates, Kuwait and Iraq export most of their crude oil through the strait, mainly to Asia.
Three ships, two in 2023 and one in 2024, were seized by Iran near or in the strait. Some of the seizures follow U.S. seizures of tankers linked to Iran.