A merchant vessel reported an explosion took place near it in the Red Sea on Thursday about 19 nautical miles west of the Yemeni port city of Mokha, British security firm Ambrey said.
Separately, the United Kingdom Maritime Trade Operations (UKMTO) said it had been informed of two explosions near a vessel 27 miles south of Mokha.
There was no damage reported, all crew were safe and the vessel was proceeding to its next port of call, the UKMTO said in a statement.
It was unclear whether the incidents reported by Ambrey and UKMTO were the same.
The vessel Ambrey reported on fit the target profile of Yemeni Houthi militants, who have attacked ships off the country's coast for several months, it said in a note.
It was en route from Europe to the United Arab Emirates and was not transmitting an Automatic Identification System signal at the time, Ambrey said. It gave no other details.
The US military said on Thursday it had destroyed eight Houthi drones and two uncrewed surface vessels in the Red Sea in the past 24 hours.
The US military's Central Command said its forces had also successfully engaged a drone launched from a Houthi-controlled area of Yemen and that Houthis had launched an anti-ship ballistic missile. There were no reports of damage or injury, it said.
Attacks on shipping routes
Houthis have made repeated drone and missile strikes on ships in the crucial shipping channels of the Red Sea, the Bab al-Mandab Strait and the Gulf of Aden since November.
This has forced shippers to re-route cargo to longer and more expensive journeys around southern Africa and has stoked fears that the Israel-Hamas war could spread and destabilise the Middle East.
The Houthi militia, which controls the most populous parts of Yemen and is aligned with Iran, says it is acting in solidarity with Palestinians fighting Israel in Gaza.