A series of drone attacks on at least seven cargo ships in the Black Sea this month has raised concerns among some NATO members that Russian President Vladimir Putin may be escalating the conflict to test the alliance’s support for Ukraine.
The attacks occurred in the exclusive economic zones of NATO members Romania and Bulgaria, threatening an important international shipping route. At least two people have been killed and 25 others remain missing, raising fears that more countries could be drawn directly into the war.
Since Russia launched its full-scale invasion of Ukraine, it has repeatedly attacked Ukrainian ports along the Black Sea and Danube River, forcing Kyiv to rely increasingly on alternative routes to export grain to Africa and the Middle East. Russian drones have also repeatedly entered Romanian airspace near Ukrainian ports along the Danube.
In the latest incidents, two ships caught fire after drone strikes on Wednesday and Thursday, with one attack occurring in Romanian territorial waters.
Romanian President Nicusor Dan said in Brussels on Thursday that two drones had hit the vessels but did not identify their origin. He warned that Romania would respond.
Suspicion has increasingly focused on Russia. Bulgarian Prime Minister Rumen Radev told parliament that Ukraine had no reason to attack its own ships and crews, arguing that Russia benefited from the incidents.
However, he acknowledged that there was no proof establishing responsibility.
Several ships hit in October
The San Marino-flagged chemical tanker Wine Trader, travelling from Tunisia to Romania, was struck by a drone on Thursday and caught fire. Five crew members were rescued, while seven remained missing.
On Wednesday, the Comoros-flagged oil and chemical tanker Yara J, travelling from Turkey to Romania, was also hit by a drone and caught fire. Romania's acting Defence Minister Radu Miruta said an investigation was underway.
Two more ships were hit off Bulgaria's coast on Tuesday. Rescuers evacuated all 15 crew members from the Ukraine-operated Chelsea 3, which sails under the Maltese flag. However, 11 crew members from the Guinea-Bissau-flagged HS Dignity remained missing.
The Chelsea 3 crew reported that three aerial drones had struck the vessel's deck and hull.
Earlier this month, sea and aerial drones attacked two other commercial ships in Bulgaria's exclusive economic zone. A Togo-flagged vessel sank, with all 12 sailors reported aboard still missing. A Bulgarian ferry evacuated 18 crew members from a damaged Palau-flagged ship.
A day earlier, a Turkish-owned cargo ship carrying corn caught fire following a drone attack and later sank off Romania's coast. Two people were killed and 11 crew members rescued. Ukrainian President Volodymyr Zelenskyy described the incident as a “horrific strike by two Russian drones on a civilian vessel” in neutral waters.
Russia's ambassador to Bulgaria said she had received no information from the Russian Defence Ministry about the incidents.
NATO's defence commitment under scrutiny
NATO Secretary-General Mark Rutte said on X on Thursday that he had met Radev and Dan to discuss Black Sea security and the latest attacks on commercial shipping.
He said NATO had strengthened its eastern flank, including by expanding its ability to counter drones, and would continue working with its Black Sea allies to adjust its deterrence and defence measures as necessary.
Article 5 of NATO's founding treaty states that an armed attack against one member is considered an attack against all. However, Romanian defence analyst Radu Tudor said it remained unclear whether the provision applied to many of the recent incidents because they occurred in the exclusive economic zones of member countries.
He said the issue had raised serious questions about how NATO would respond, arguing that the alliance had been too slow to act in the Black Sea.
“Words are not enough,” Tudor said, warning that repeated incidents were bringing Russia closer to NATO's borders.
Growing security concerns
The latest attacks are part of a broader series of drone incursions affecting Romania and other NATO members since Russia's invasion of Ukraine. Most have been attributed to Russian drones, although Ukrainian drones have also crossed national borders.
In August, Romania deployed two F-16 fighter jets to destroy a naval drone reportedly carrying explosives near a major Black Sea gas project. Miruta said the decision was made to protect the lives of hundreds of people working on the gas platform.
A Romanian defence sector source, who spoke to The Associated Press on condition of anonymity because they were not authorised to comment publicly, said the attacks appeared aimed at damaging Ukraine's economy rather than targeting Romania directly.
The source said Romanian authorities had spent the summer recovering various types of drone debris from the sea and beaches, adding that the situation required action if it continued.
The source also said Turkey might seek to bring together countries bordering the Black Sea to discuss escorting commercial convoys through a protected maritime corridor.
However, the source warned that such an operation would be risky because Romanian naval vessels lacked air-defence systems capable of protecting ships against drones.
In July, Romania, Bulgaria and Turkey expanded their Black Sea Mine Countermeasures Task Force agreement to include the protection of critical underwater infrastructure. Romania's Defence Ministry said the arrangement would include a permanent naval presence in the country's exclusive economic zone.
Organising escorts would also be complicated because commercial vessels often fly one country's flag while being owned by companies based elsewhere, the source said.
Bulgarian Defence Minister Dimitar Stoyanov said on Wednesday that his country planned to join NATO's Drone Edge project by the end of October. Launched in July, the initiative, which Romania has also joined, aims to invest more than $40 billion in counter-drone capabilities over the next five years.
Shipping insurance costs rise
Cezar Gheorghe, founder of grain consultancy Agricolumn, told the AP that the drone attacks had not yet negatively affected trade at Romania's Black Sea port of Constanta.
However, he warned that insurance costs were rising across the wider Black Sea region, increasing expenses for ships travelling through the Bosphorus Strait and towards Constanta.
Gheorghe said his main concern was the possibility of a serious incident at or near the port. In June, a Ukrainian maritime drone exploded at the port, with three others exploding nearby.
“It's a matter of time,” he said, expressing concern about the risk of another serious incident.