The United Kingdom Maritime Trade Operations reported the hit early on Sunday.
The status of the crew, the extent of any damage and the environmental impact were not immediately known, the agency said.
Unlike in most previous incidents, UKMTO did not give the exact location of the attack, leaving it unclear whether the vessel was hit off the coast of Oman or closer to Iran.
It also remained unclear who was responsible.
Iran continues to largely disrupt shipping through the strait with threats and attacks on vessels.
The Strait of Hormuz is a vital route for exports of oil, liquefied natural gas and fertiliser from Gulf states. The disruption has had consequences for the global economy.
The waterway has become a central flashpoint in the war between the United States and Iran. Before the conflict, the strait was open to shipping.
Meanwhile, Saudi Arabia has shut down its East-West pipeline, after the vital oil conduit came under aerial attack in the widening Middle East war, threatening to send energy prices even higher.
The world's largest crude oil exporter said it temporarily closed the pipeline as a precaution after a drone attack that both Baghdad and Riyadh said had originated in Iraq, where Iranian-backed militias operate.
Iraq dismissed a military commander on Saturday in response to the attack.
The 1200km pipeline running across the Arabian Peninsula has served as the main route out for global supplies of Middle East oil for the past six months while the Strait of Hormuz has been largely shut by war.
It has been moving four million to five million barrels per day, amounting to 4.0 per cent to 5.0 per cent of global supply, sparing Saudi Arabia the brunt of the disruption that has crippled other Gulf oil and gas exporters.
There was no immediate claim of responsibility for the strikes.
Satellite images showed black smoke rising from an area of the pipeline south of Medina.
The attack resulted in some injuries and damage that was being assessed, the Saudi Foreign Ministry said without detailing the impact on exports.
with Reuters