Two commercial ships were hit by drones in the Black Sea off Bulgaria on Tuesday, sinking one vessel and prompting emergency rescue operations, Bulgarian officials said.

Prime Minister Rumen Radev said the strikes occurred roughly 20 and 21 miles from Bulgaria’s coast. The precise origin of the drones was not immediately established, and no responsible party should be assigned without further evidence.

The Guinea-Bissau-flagged cargo ship Dignity sank after what Bulgarian officials described as a military strike. The Associated Press reported that five sailors had been rescued while the search continued for 11 others.

A second vessel, the Ukrainian-operated coastal freighter Chelsea 3, was sailing under the Maltese flag. AP reported that all 15 members of its crew were evacuated and that five people were treated for minor injuries. The crew included Ukrainian and Azerbaijani citizens, according to the report.

The attacks took place outside Bulgaria’s territorial waters but inside the country’s wider maritime security environment. That distinction matters: a strike in an exclusive economic zone is not the same as an attack inside territorial waters, but it can still force a coastal state to mobilise rescue services, review navigation warnings and consider how civilian traffic is being protected.

The incident also raises questions for the wider Black Sea shipping corridor. Commercial vessels continue to operate in waters connected to the war in Ukraine, where mines, missiles, drones and disputed military activity have repeatedly complicated civilian navigation. A new attack on merchant ships could increase insurance costs and make operators more cautious about routes that are already exposed to conflict-related risk.

Bulgarian authorities were still dealing with the immediate rescue effort when the reports emerged. The number of missing sailors, the nature of the damage and the identity of those responsible all require continuing confirmation.

What is already clear is the civilian consequence: a cargo ship has been lost, another has been damaged, and crews have been placed in danger in a part of the sea where commercial shipping is expected to remain separate from the fighting.