British security firm Ambrey said on Saturday it had received information that a Panama-flagged crude oil tanker had been attacked approximately 10 nautical miles southwest of Yemen's Mokha.
Ambrey said a radio communication indicated the vessel was hit by a missile and that there was a fire onboard. It did not provide details of the communication.
Yemen's Houthi militia, which controls the most populous parts of Yemen and is aligned with Iran, has staged attacks on ships in the waters off the country for months in solidarity with Palestinians fighting Israel in Gaza.
Vessels in the vicinity were advised to exercise caution and report any suspicious activity, Ambrey added in an advisory note.
Earlier Houthi attacks on Saturday
Earlier on Saturday, the United Kingdom Maritime Trade Operations (UKMTO) agency said a vessel in the Red Sea was struck by an unknown object and sustained slight damage.
"The vessel and crew are safe and continuing to its next port of call," UKMTO said in an advisory note, adding the incident occurred 76 nautical miles northwest of Yemen's Hodeidah.
Months of Houthi attacks in the Red Sea have disrupted global shipping, forcing firms to re-route to longer and more expensive journeys around Southern Africa, and stoking fears that the Israel-Hamas war could spread to destabilize the wider Middle East.
The United States and Britain have carried out strikes against Houthi targets in response to the attacks on shipping.