Two vessels came under drone attack in the Black Sea off Bulgaria's coast, and one of them went down, according to Bulgarian Prime Minister Radev. Eleven crew members from the sunken ship are still unaccounted for, while one person from that vessel was pulled from the water. Rescue teams are continuing to search for the missing.
The ship that stayed afloat, the Ukrainian-owned Chelsea 3, was sailing under the Maltese flag. Radev said it was struck by three drones at about 01:30 local time while it was roughly 33 kilometers off the coast near Byala. Everyone aboard that vessel — seven Ukrainians and eight Azerbaijanis — was rescued. Five of them received medical treatment, and none of the injuries were serious, according to NOS.
Radev called the attack unacceptable and described it as a serious violation of international law. He summoned Russia's ambassador in Bulgaria and said he had also been in contact with NATO and the European Union. In a televised address, he said the strike had taken place close to Bulgarian territorial waters and that he would discuss it with NATO chief Mark Rutte.
Why it matters
Bulgaria does not share a border with Ukraine or Russia, but as a NATO member it sits at a strategic point on the Black Sea, where both Ukraine and Russia operate major ports. The location gives the attack weight beyond its immediate toll: it happened near the waters of an alliance state, not in a distant conflict zone.
The strike also fits a pattern that has been building over the past week. Exactly seven days earlier, another ship sank off the Bulgarian coast after a drone attack, and a fire broke out on a second vessel. Eighteen crew members were rescued in that episode. Radev blamed Russia for it at the time. Moscow has not responded to either incident, NOS reports.
Concern among NATO allies about hybrid drone attacks has been rising, and Russia is widely held responsible for them while it continues its war against Ukraine, now past the four-and-a-half-year mark.
NATO signals it will adjust its eastern posture
After speaking with Radev, Rutte said the alliance would keep adjusting its military presence along the eastern flank as needed. He said NATO had already strengthened its position there and would keep monitoring the security situation, adapting its deterrence and defense stance when required.
European Commission President Ursula von der Leyen framed the Black Sea as a new front in the escalation of Russia's war against Ukraine. She, too, called the attacks unacceptable.
The question of who carried out the strike has not been settled publicly. Radev's government has pointed toward Russia, but no claim of responsibility has been confirmed, and the Russian side has stayed silent on both the latest attack and the one a week earlier. That silence leaves the official account resting on Bulgaria's assessment rather than on any admission or independent finding.
What is known about the two ships
The Chelsea 3, the vessel that survived, is Ukrainian-owned and was flying the Maltese flag when it was hit. Its crew of fifteen was fully accounted for after the rescue. The second ship sank, and the search for its eleven missing crew members is the most urgent part of the response. One survivor from that vessel was recovered.
The attacks took place in international waters off Byala, a location Bulgarian officials stressed was close to the country's territorial waters. That proximity is central to how Sofia has characterized the incident — not as a remote maritime event but as a strike in its immediate neighborhood.
Bulgaria's response has moved on several tracks at once: a diplomatic summons to Russia's ambassador, outreach to NATO and the EU, and a direct conversation between Radev and Rutte. The prime minister's language in his televised remarks was blunt, calling the attack absolutely unacceptable and noting it was the second such strike near Bulgarian waters.
A week of escalation at sea
The two episodes are close enough in time and method to be read together. In the earlier attack, one ship sank and another caught fire; eighteen people were rescued. In the latest, one ship sank and another was hit but remained afloat, with its crew brought to safety. In both cases, Bulgaria's prime minister assigned responsibility to Russia.
Von der Leyen's comment places the incidents inside a broader frame: the Black Sea as a theater where the war's effects are spilling beyond Ukraine's own coastline. For NATO, the practical consequence is a continuing review of how much force to keep along the eastern edge of the alliance, and how quickly that posture can shift if attacks near member states continue.
What happens next will turn on two things: whether the search off Byala finds the eleven missing crew members, and whether NATO's promised adjustments to its eastern flank translate into concrete deployments. Russia's silence, so far, remains unbroken.
