photo released by the European Naval Mission in the Red Sea shows smoke rising from the MV Delta Sounion on Sunday.Credit...EUNAVFOR ASPIDES/EPA, via Shutterstock 
The attack, off the southwest coast of Yemen, was the first such incident reported in the vital shipping corridor since mid-April.
Maritime security sources said the vessel, which they identified as the Liberian-flagged, Greek-owned bulk carrier Magic Seas, had taken on water after being hit by sea drones.
It was first targeted by gunfire and self-propelled grenades launched from eight small boats, with armed security on the ship returning fire, the United Kingdom Maritime Trade Operations and Ambrey said in advisories.
Ambrey said in a separate advisory that the ship was later attacked by four Unmanned Surface Vehicles.
"Two of the USVs impacted the port side of the vessel, damaging the vessel's cargo," Ambrey added. UKMTO said the attack resulted in a fire onboard and that the incident was ongoing.
There were no reports of injuries among the crew, a source at maritime security company Diaplous said. The vessel's operator was not immediately available for comment.
No one immediately claimed responsibility for the attack, but Ambrey assessed the vessel "to meet the established Houthi target profile".
Sunday's attack occurred 51 nautical miles southwest of Yemen's port city of Hodeidah, the UKMTO and Ambrey said.
Tensions in the Middle East remain high over the war in Gaza and after the 12-day Israel-Iran war and airstrikes by the United States on Iranian nuclear sites in June.
Yemen's Iran-aligned Houthis launched more than 100 attacks targeting shipping from November 2023, saying they were acting in solidarity with Palestinians over Israel's war with Hamas.
During that period, the group sank two ships, seized another and killed at least four seafarers in an offensive that disrupted global shipping, forcing firms to reroute, prompting the U.S. to intensify attacks on the group this year.
In May, President Donald Trump announced the U.S. would stop bombing the Houthis in Yemen, saying that the group had agreed to stop interrupting important shipping lanes in the Middle East.
Under the agreement, neither the U.S. nor the Houthis would target the other, including U.S. ships in the Red Sea and Bab al-Mandab Strait, Oman said in a statement at the time.
Later in June, Yemen's Houthis threatened to target U.S. ships in the Red Sea if Washington became involved in Israeli attacks on Iran. They have not specified whether they will follow through on their threat after the U.S. attacked Iranian nuclear facilities last month.
(Reporting by Muhammad Al Gebaly, Jaidaa Taha, Hatem Maher and Yannis Souliotis; Editing by Alison Williams, Emelia Sithole-Matarise and Alex Richardson)