Two drone strikes on merchant ships in Bulgaria's Black Sea exclusive economic zone on Saturday resulted in one vessel sinking and a multi‑agency rescue effort, officials said. The attacks, which occurred about 18 nautical miles off the coastal town of Biala, have prompted the Bulgarian government to summon the Russian ambassador, condemn the aggression as an escalation of the war in Ukraine, and call for a NATO Article 4 consultation.
Incident details
According to Bulgarian state media, the first unmanned aerial system hit a cargo ship that was sailing within the country's 12‑nautical‑mile economic zone, causing damage but no immediate sinking. A second drone struck a nearby vessel, which subsequently took on water and sank, prompting the deployment of coast‑guard vessels, naval units and civilian rescue teams. International news agencies reported that the sinking occurred within the same 18‑nautical‑mile radius from Biala, a location that lies well inside Bulgaria’s sovereign maritime area.
Both drones were described as “small” and “unmanned” by multiple outlets, though no specific type or origin was confirmed. The Bulgarian Ministry of Defence has not released the exact number of casualties, but the rescue operation retrieved all crew members from the sunken ship without reported fatalities. The incident marks the latest in a series of unmanned‑aircraft attacks on merchant traffic in the Black Sea, an area already contested by Russian forces supporting Ukraine.
Political and diplomatic response
President Rumen Radev immediately called Defence Minister Dimitar Mitrofanov to discuss the situation, emphasizing the need for a swift and coordinated response. In a televised address, Radev announced that Bulgaria would summon the Russian ambassador to the Ministry of Foreign Affairs “to convey our strong condemnation of the attacks and demand an explanation.” The Russian embassy confirmed that the ambassador had been summoned but did not comment on the incident.
"We must request a NATO Article 4 consultation," former Defence Minister Stefan Tagarev told reporters, urging the alliance to assess the security implications of the attacks.
Tagarev’s statement, reported by Dnevnik.bg, reflects growing pressure within Sofia to invoke NATO’s collective defence mechanisms. Article 4 allows a member state to call for consultations when its territorial integrity, political independence or security is threatened. While no formal request has been lodged yet, the Bulgarian government has indicated that it will brief NATO allies in the coming days.
The European Union’s response was swift. Commission President Ursula von der Leyen described the drone strikes as “unacceptable” and called for a “strong and unified response” from the bloc. Both the EU and Ukraine issued statements condemning the attacks and reaffirming support for Bulgaria’s right to protect its maritime borders.
Regional and NATO implications
Analysts note that the attacks underscore the widening reach of Russian‑linked aggression beyond Ukrainian waters. The Black Sea has been a focal point of tension since Russia’s 2022 invasion of Ukraine, with frequent incidents involving missiles, mines and drones targeting commercial and military vessels. The latest strikes near a NATO member’s coast raise concerns about the alliance’s ability to safeguard the security of its eastern flank.
NATO’s Secretary‑General has not yet issued a formal statement, but a spokesperson confirmed that the alliance is monitoring the situation closely and that member states are exchanging information on the incidents. The possibility of an Article 4 consultation, if pursued, would be the first such request by a NATO country since the alliance’s expansion to the Balkans, highlighting the seriousness with which Sofia views the threat.
In the immediate aftermath, Bulgarian authorities have stepped up patrols along the Black Sea coast, and the navy has been tasked with enhancing surveillance of the airspace over the economic zone. The government also announced that it will review its maritime security protocols and consider additional defensive measures, including potential deployment of anti‑drone systems.
While the exact perpetrators of the drone attacks remain unidentified, the prevailing assessment among Bulgarian officials is that the strikes are linked to Russian operations aimed at destabilising regional trade routes and pressuring NATO allies. The incident has therefore become a focal point of domestic debate in Bulgaria, where security concerns dominate public discourse and the government’s handling of the crisis will likely influence upcoming political developments.
