Eleven sailors were reported missing after a drone attack sank a cargo ship off Bulgaria's Black Sea coast on Tuesday. A second vessel was also struck, leaving five crew members injured.
The attacks occurred early on October 13, just outside Bulgarian territorial waters. The cargo ship HS Dignity sank near the Romanian border. Five of its 16 crew members were rescued, while authorities launched a search for the remaining 11.
A second vessel, the Ukrainian-operated Chelsea 3, was struck by three aerial drones farther south. All 15 crew members were rescued, although five required medical assistance. Bulgarian authorities said three were hospitalised with burns, including one sailor who also suffered a mild head injury.
Responsibility for the attacks remains unconfirmed. Ukrainian Foreign Minister Andrii Sybiha accused Russia of carrying out the strikes, while Bulgarian Prime Minister Rumen Radev acknowledged that investigators lacked sufficient evidence to identify those responsible.
Radev nevertheless argued that the attacks benefited Russia and summoned Moscow's ambassador to Sofia.
Russia's ambassador said she had received no information from Russia's Defence Ministry concerning the attacks and raised the possibility of a provocation by a third party.
Describing the attacks as "absolutely unacceptable", Radev sought assistance from NATO and the European Union to strengthen maritime and airspace surveillance.
NATO Secretary-General Mark Rutte said the alliance would continue monitoring the security situation and adjust its deterrence and defence posture along its eastern flank as necessary.
The incidents follow similar attacks on October 6, when drones struck two commercial vessels in Bulgaria's Black Sea economic zone. One ship sank, and its crew remained unaccounted for after an unsuccessful rescue operation. The crew of the second vessel was rescued.
Bulgaria is also seeking closer cooperation with Romania and Turkey to protect commercial shipping. Bulgarian President Iliana Iotova said the country would raise the growing threat to maritime safety at the United Nations Security Council.
The attacks have heightened concerns about shipping routes used by Russia and Ukraine, both major grain exporters.
On October 13, United Nations spokesperson Stéphane Dujarric condemned the attacks on civilian shipping, warning that the expanding disruption to maritime trade could affect global commodity prices and endanger seafarers.
