At least three sailors were killed in attacks on four merchant ships in the western Black Sea on 5 and 6 October. The crew of one of the ships, the Alfa Watan, sunk inside Bulgaria's exclusive economic zone, was missing on 6 October.

Rustam Hasanov, the captain of the Royad Mammadov, was killed when the ship caught fire and sank off Romania on 5 October, Azerbaijan's Foreign Ministry said. Hasanov, an Azerbaijani national, was born in 1974. The ministry said a second Azerbaijani crew member, Mahammad Suleymanzade, born in 2002, was missing and that three other Azerbaijani sailors were being treated in hospital. It said it was arranging "the repatriation of the body of the deceased."

Romania's Interior Ministry said rescuers recovered two bodies from the Royad Mammadov and rescued 11 crew. Kyiv Post reported that the crew member whose fate had been unknown was later confirmed dead.

Oleh Kiper, governor of Ukraine's Odesa region, said a Russian drone struck a Marshall Islands-flagged ship carrying rapeseed oil on 6 October, killing one crew member and injuring seven. The ship's superstructure caught fire. "By deliberately striking civilian shipping and port infrastructure, Russia is grossly violating the norms of international law, creating a threat to global food security," Kiper said.

Alfa Watan sinks off Bulgaria

Bulgarian Prime Minister Rumen Radev said sea and aerial drones struck two commercial vessels at about 3am local time on 6 October, roughly 128 kilometres off the coast near Byala. Both ships were inside Bulgaria's exclusive economic zone, and the strikes were the first on shipping in that zone, Radev said.

Radev said the Togo-flagged Alfa Watan suffered critical structural damage and sank at the scene. Rescue teams coordinated from Varna by Rumen Nikolov, head of local rescue operations, found an overturned boat, life rafts and life jackets, according to Bulgarian and Turkish media reports. Defence Minister Dimitar Stoyanov said helicopters and aircraft had joined the search.

The Palau-flagged Able caught fire after the strike. A Bulgarian ferry took off all 18 crew members, 11 of them Turkish and seven Indian, according to Türkiye Today. Two sailors with severe injuries, one with burns and one with a head injury, were flown to hospital in Varna.

Türkiye Today reported that Istanbul-based Ocean Eagle owns the Able and Mersin-based Baraka Shipping owns the Alfa Watan. Radev said the Able was carrying wheat and sailing south, while the Alfa Watan was heading north with an unknown cargo.

Radev told reporters after an emergency government meeting: "This is an unacceptable attack in Bulgaria's exclusive economic zone. It is a blatant violation of international law and maritime law."

Royad Mammadov sinks off Romania

Romania's Coast Guard was alerted at about 11am local time on 5 October to a fire on the Royad Mammadov, a 140-metre general cargo ship flagged to Saint Kitts and Nevis, Romania's Interior Ministry said. The vessel was about 30 nautical miles (55 kilometres) south of Sfantu Gheorghe in Tulcea County, inside Romania's exclusive economic zone and outside its territorial waters.

"Eleven crew members have been rescued. Two deceased individuals have also been located," the ministry said. A helicopter lifted injured sailors off the ship by winch. India's embassy said three Indian sailors were aboard and that one injured Indian crew member was treated at Constanta County Hospital. Kyiv Post reported that 13 crew were aboard and that Turkish company MG Shipping 5 Co Ltd owns the ship.

MarineTraffic data showed the Royad Mammadov had left the Ukrainian Danube port of Izmail bound for Italy. Outlook India and Kyiv Post reported its destination as Ravenna, with arrival scheduled for 12 October. Ukrainian outlet Militarnyi reported that the ship's AIS signal cut out at about 9:20am local time.

Romanian news channels reported that one or more drones struck the ship southeast of a Black Sea oil platform. Romanian authorities described the incident as a fire on board.

Ukrainian President Volodymyr Zelenskyy wrote on X that the ship had been hit in "a horrific strike by two Russian drones on a civilian vessel" in neutral waters. He said the ship was Turkish-owned, carried corn and had Azerbaijani and Indian nationals aboard, and that the captain was among the dead.

"Russia consistently chooses terror and sinking civilian vessels instead of normal maritime navigation," Zelenskyy wrote.

Ambassador Manoj Mohapatra visited the Indian crew in hospital and said they were "in good health and receiving necessary care."

Blame for the Bulgarian strikes

Radev said he could not yet say which country sent the drones. "We are still trying to establish where the attack came from," he said. He said the drones were "either Russian or Ukrainian."

A Turkish sailor from the Able blamed Russia when he came ashore in Varna. "I'm from Türkiye. I think the Russians dropped a depth charge on us, a fire broke out. It wasn't a drone, it was underwater. I think it was Russian because we were carrying Ukrainian cargo," he said, according to The Sofia Globe.

Zelenskyy said Ukraine's forces had not carried out any operations in that part of the sea and that the attack continued Russia's efforts "to make the western part of the Black Sea completely unfit for navigation," Censor.net reported. Reuters reported that initial assessments suggested Russia had probably carried out the strike.

Russia's Defence Ministry said on 6 October that its drones struck targets overnight in Ukraine's Odesa region, including an ammunition depot, a bulk carrier in the port of Chornomorsk that it said was carrying dual-use goods and port infrastructure in Izmail. The ministry also said Russian air defences intercepted nearly 900 Ukrainian drones overnight over Russian regions, occupied Crimea and the Sea of Azov.

Bulgaria, NATO and the EU

Radev said he had informed the EU Council and NATO. He said Bulgaria had no need to invoke Article 4 or Article 5 of the NATO treaty, because "more serious" attacks had already hit Poland and Romania, "where an apartment building was also hit."

Radev said the ships were hit outside Bulgarian territorial waters. "This is 130 km from our coast, it falls within our economic zone, but these are not yet territorial waters, they are considered neutral," he said. He also said the war was spreading geographically as it intensified, and that the attacks were "driving up insurance costs even further and making shipping extremely difficult."

NATO declined to comment and referred questions to Bulgarian authorities. In September, NATO's top commander, US General Alex Grynkewich, urged member states to publicly name those they hold responsible for drone incidents and sabotage once they have sufficient evidence. Germany took almost a month to publicly blame Russia for an attempted attack on 4 August at Leipzig/Halle Airport with an explosives-laden drone.

European Commission President Ursula von der Leyen wrote on X that "the situation in the Black Sea is increasingly concerning" and that "attacks on civilian shipping are unacceptable." Hungarian Prime Minister Peter Magyar said Hungary stood in full solidarity with Bulgaria, Al Jazeera reported.

President Iliana Yotova called a meeting of Bulgaria's Consultative Council on National Security for 7 October on maritime security and critical infrastructure. Yotova took office in January 2026, and the 7 October session will be the first she has convened. The law requires the council to meet at least every three months. Opposition parties criticised her again on 6 October for failing to call it.

Bulgaria's Environment Ministry ordered water sampling at Cape Kaliakra, Byala and Sozopol to test for petroleum products, polychlorinated biphenyls and metals.