Bulgarian Prime Minister Rumen Radev summoned Russian ambassador Eleonora Mitrofanova after two merchant vessels were struck by drones off Bulgaria's Black Sea coast. One ship, the Guinea-Bissau-flagged HS Dignity, sank 17 nautical miles east of Krapets with 10 crew missing and six rescued. The other vessel, the Ukrainian-owned Chelsea-3, was hit 18 nautical miles from Byala with all 15 crew rescued, though five sustained minor injuries.
The attacks occurred within Bulgaria's exclusive economic zone but outside its territorial waters. Radev told reporters the logic of the strikes "benefits the Russian Federation," though he acknowledged no conclusive evidence of blame had been established. Ambassador Mitrofanova told Radev she had no information from Russia's defence ministry about the attacks and suggested a third party might have staged them as provocation.
Bulgaria's Defence Minister Dimitar Stoyanov told reporters he assumed the drones were Russian, describing it as "illogical" for Ukraine to target its own ships. He noted escalation is "steadily increasing" and the conflict is "drawing ever closer to our territorial waters."
The incidents follow similar attacks on 6 October, when the Maltese-flagged Alfa Watan sank in the same zone with 10 crew presumed dead, including nine Syrians.
Because the strikes occurred outside Bulgarian territorial waters, NATO Article 5 was not triggered. Radev spoke with NATO Secretary General Mark Rutte, who said the alliance would "continue to work closely with our allies in the Black Sea" and monitor the security environment. Bulgaria is a NATO member.
Ukraine's Foreign Minister Andrii Sybiha directly accused Russia of the attacks, saying Moscow "demonstrates deliberate disregard for civilian lives and maritime security." European Commission President Ursula von der Lejorden called the Black Sea "another front of escalation of the Russian war in Ukraine."
Russia's military has not publicly commented. Moscow says it targets vessels delivering weapons and dual-use cargo to Ukraine, citing recent strikes on ports in Mykolaiv and Chornomorsk. Kyiv and European allies counter that merchant ships carrying grain and civilian cargo are being attacked. Turkey has called on both countries to halt Black Sea attacks.