In October, drones attacked nine merchant ships off the coast of Bulgaria and Romania — AP

Over the course of 24 days in October, drones struck nine merchant ships and tankers in the Black Sea off the coast of Bulgaria and Romania.

At least 30 sailors were killed or missing, the Associated Press reported.

According to the agency, air and sea drone attacks on civilian vessels off the coast of NATO countries are creating new threats to shipping in the Black Sea. The Bulgarian border police are increasingly involved in rescue operations at sea.

In one recent incident, border guards rescued the crew of the Maltese-flagged dry cargo ship Chelsea 3, which was operated by a Ukrainian operator. The ship was hit by three drones.

Despite strong winds and high waves, rescuers managed to evacuate all 15 crew members of the damaged vessel.

According to Nikolai Monev, commander of the border police base in Sozopol, the unit maintains constant readiness to respond to emergencies at sea, including drone attacks.

The base, established in 2013 with EU funding, has between two and five vessels on duty at all times. Border guards use coastal radars, thermal imagers and daytime surveillance cameras to monitor the sea area.

At the same time, Russian forces continue to attack Ukrainian port infrastructure in the Black Sea and the Danube. Against the backdrop of an increase in the number of incidents near Bulgaria and Romania, concerns about the safety of civilian shipping throughout the Black Sea region are growing.

USM previously reported that fragments of a drone were found on board the Chelsea 3 vessel attacked in Bulgaria’s exclusive economic zone. They are being examined to determine the type of drone used to attack the vessel on October 13.