British security firm Ambrey said on Thursday a fire was spotted in the Red Sea approximately 58 nautical miles southwest of Yemen's port of Salif.
A nearby vessel observed smoke coming from the water, an incident likely related to the destruction of an unmanned surface vessel, Ambrey said.
"Hostile manned, and unmanned craft, have been operating in the area," Ambrey added.
Iran-aligned Houthi militants based in Yemen have launched attacks on international shipping in the Red Sea region since November in solidarity with Palestinians in the war between Israel and Hamas.
In response shipowners have rerouted many vessels away from the Red Sea and Suez Canal to the longer route around the southern tip of Africa, meaning higher costs and longer delivery times.
