Bucharest: The growing number of attacks on commercial vessels in the Black Sea is raising security concerns in NATO members Romania and Bulgaria, as the Russia Ukraine war increasingly threatens maritime trade and regional stability.
A series of incidents involving cargo ships and tankers has raised fears that the conflict could spread beyond Ukraine and Russia, placing neighbouring countries and international shipping routes at greater risk. NATO has responded by strengthening surveillance and counter drone capabilities along its eastern flank.
The latest major incident occurred on October 28, when the Greek managed, Liberian flagged container ship CONTSHIP JET sank after being struck by three naval drones in Bulgaria's exclusive economic zone, about 21 nautical miles southeast of Shabla. The vessel was outside Bulgaria's territorial waters.
All 18 crew members were rescued. They included 14 Filipinos and four Ukrainians. The vessel was travelling from Haifa, Israel, to Constanța, Romania, carrying 421 containers. Its cargo reportedly included lithium ion batteries, corrosive liquids, acids and industrial components.
Maritime security company Ambrey assessed that the unmanned surface vehicle resembled a variant of the Russian Murena 300S design. However, this similarity does not establish who launched the drones. Responsibility for the attack remains unconfirmed, and Russia has denied involvement in the recent incidents.
The sinking was part of a wider series of maritime attacks recorded during October. At least nine cargo ships and tankers were struck, damaged or sunk in incidents involving waters near Romania and Bulgaria between October 5 and October 28.
The incidents included attacks on vessels near the Romanian and Bulgarian coasts, with several crew members killed or reported missing. On October 5, the cargo vessel Royad Mammadov was struck south of Sfântu Gheorghe, Romania, leaving two crew members dead. Other incidents occurred near the Bulgarian coast and in waters close to the Romanian port of Constanța.
Romania has also experienced repeated drone incidents involving its national airspace. On October 17, Romanian F16 fighter aircraft destroyed two attack drones over Romanian territorial waters after they were detected approximately 120 kilometres east of Snake Island.
Romania's Ministry of National Defence said the aircraft were scrambled from the 86th Borcea Air Base. The first drone was destroyed at 6:01 p.m. and the second at 6:05 p.m. Both were identified as jet propelled attack drones belonging to the Geran family.
The repeated incidents have increased pressure on NATO to strengthen security in the Black Sea region. NATO Secretary General Mark Rutte has reaffirmed the alliance's commitment to protecting its members and said that additional surveillance and counter drone capabilities would be provided along its eastern flank.
The measures include additional maritime patrol aircraft, radar systems and drones to improve monitoring and strengthen the ability to respond to potential threats. Romania has also called for additional air defence interceptors and radar capabilities to protect its territory and critical infrastructure.
France has contributed to regional surveillance by deploying an Atlantique 2 maritime patrol aircraft to Romania. The aircraft has been assigned duties over the western Black Sea to monitor maritime activity and help identify potential threats to shipping and critical infrastructure.
Romania, Bulgaria and Turkey have also agreed to improve their cooperation. Their defence ministers met in Sofia on October 28 to discuss the growing threats facing commercial shipping and regional maritime security.
The discussions focused on sharing intelligence, strengthening surveillance, improving early warning systems and coordinating naval operations. The three countries also stressed the importance of protecting civilian vessels and maritime infrastructure.
Turkey has an important strategic position in the region because it controls access between the Mediterranean and Black Sea through the Bosphorus and Dardanelles under the Montreux Convention.
Bulgarian Prime Minister Rumen Radev said his government had shared available video footage and evidence of the October 28 incident with its allies. He said investigations were continuing to establish the origin of the drones.
Radev also reported that a French patrol aircraft had detected the drones about 30 minutes before the attack and provided information about their flight path. He said Bulgaria had raised the incidents with the United Nations, NATO and European Union officials.
Although Russia is suspected by some military analysts of being involved in the attacks, responsibility for individual incidents has not been conclusively established. Some analysts believe the attacks could be testing NATO's willingness to respond to security threats near its eastern borders. Moscow has denied involvement.
The scale of the maritime security problem has also increased. Ambrey Analytics recorded 317 vessels hit in the Black Sea and Sea of Azov between May and October, compared with 74 during the preceding six months. These figures cover reported vessel incidents and do not mean that all the ships were sunk or destroyed.
The situation has raised questions about NATO's collective defence responsibilities. Under Article 5 of the North Atlantic Treaty, an armed attack against one NATO member is considered an attack against all members. However, the alliance assesses the circumstances of each incident, and Article 5 does not automatically apply to every security incident involving a member country.
The location of an attack is also important. A country's territorial waters extend up to 12 nautical miles from its coast, while its exclusive economic zone can extend up to 200 nautical miles. A country exercises sovereignty over its territorial waters, but other states retain certain navigation and overflight rights within an exclusive economic zone under international law.
The attacks are also affecting trade and food security. Ukraine has increasingly relied on alternative export routes through the Danube River and Romanian ports after suspending operations at its Black Sea ports in late July because of Russian attacks.
Government data cited in international reporting showed that Ukraine's grain exports through ports fell to 810,000 metric tonnes in September 2026, compared with 2.1 million metric tonnes in September 2025.
Russian grain exports through the Black Sea and Sea of Azov also declined sharply, from 4.74 million metric tonnes in September 2025 to 300,000 metric tonnes in September 2026.
The Black Sea is an important route for grain, fertiliser, oil and other commodities. Further disruption could affect international food supplies, shipping costs and energy markets, particularly in countries across Africa and the Middle East that depend on imported agricultural products.
Romania's offshore energy infrastructure is another concern. The Neptun Deep gas project in the Black Sea is expected to make Romania the European Union's largest gas producer in 2027. Previous drone incidents near the project have increased concerns about the security of offshore energy facilities.
As attacks on commercial shipping continue to raise regional security concerns, Romania, Bulgaria and Turkey are seeking closer cooperation while NATO strengthens its defensive presence. However, the origin of several attacks remains under investigation, and there is no confirmed indication that the alliance has decided to enter the conflict.