A string of drone attacks on at least seven cargo vessels in the Black Sea this month, off the coasts of NATO members Romania and Bulgaria, has some members of the alliance wondering if Russian President Vladimir Putin is seeking escalation to test their support for Ukraine in its war against Moscow's full-scale invasion.
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The attacks in the two countries' exclusive economic zones threaten a global shipping route and have left two people dead, with at least 25 still missing. They also run the risk of drawing other countries directly into the war for Ukraine.
Throughout the war, Russia has repeatedly bombarded Ukraine's Black Sea and Danube River ports, leaving Kyiv increasingly reliant on alternative routes to get its grain exports to markets in Africa and West Asia. Russian drones have repeatedly violated Romanian airspace near some of Ukraine's Danube ports.
In the latest incidents, fires broke out on two ships struck by drones on Wednesday (October 14, 2026) and Thursday (October 15), one in Romania's territorial waters.
Romanian President Nicușor Dan said Thursday (October 15) in Brussels that “two drones” had hit the vessels but did not say whose drones they were. “There will be a reaction from the Romanian state,” he warned.
Increasingly, the suspicion falls on Russia. “There is no logic in Ukraine attacking its own ships and crews, given that the outcome of all these attacks favours Russia — and indeed, the logic points in that direction,” Bulgarian Prime Minister Rumen Radev told his country's Parliament.
“The problem is that we cannot prove it.”
Multiple vessels struck by drones in October
The San Marino-flagged Wine Trader, a chemical tanker travelling from Tunisia to Romania, was struck by a drone on Thursday (October 15) and caught fire. Five crew members were rescued but another seven are missing.
On Wednesday, a drone strike and fire were reported on the Comoros-flagged Yara J, a chemical and oil tanker travelling from Turkey to Romania.
Romania's acting Defence Minister Radu Miruta said an investigation was underway.
On Tuesday, two ships were struck by drones off Bulgaria's coast. Rescuers evacuated all 15 crew members from the Ukraine-operated Chelsea 3, sailing under a Maltese flag, but 11 crew members from the Guinea-Bissau-flagged HS Dignity are still missing.
The crew of the Chelsea 3 reported the ship's deck and hull were hit by three aerial drones.
Earlier this month, sea and aerial drones attacked two other commercial vessels in Bulgaria's exclusive economic zone. A Togo-flagged ship sank with no sign of the 12 sailors reported on board, while a Bulgarian ferry evacuated 18 crew members from a Palau-flagged vessel that was damaged.
A day earlier, a Turkish-owned cargo ship carrying corn caught fire following a drone attack and later sank off the coast of Romania. Two people died and 11 crew members were rescued.
Ukrainian President Volodymyr Zelenskyy described the attack as “a horrific strike by two Russian drones on a civilian vessel” in neutral waters.
Russia's ambassador in Sofia, Bulgaria, said she didn't have any information from the Russian Defense Ministry.
NATO's defense clause under scrutiny
NATO Secretary-General Mark Rutte said on X on Thursday (October 15) that he met Radev and Dan to discuss security in the Black Sea and “the latest attacks on commercial shipping.”
“NATO has strengthened our posture along the eastern flank including with increasing counter-drone capabilities,” he said. “NATO will continue to work closely with our Allies in the Black Sea, adjusting our deterrence and defense posture as needed.”
Article 5 of the NATO charter has a mutual defence guarantee — an attack on one is an attack on all — but Romanian defence analyst Radu Tudor said it was uncertain as to whether it covers many of the Black Sea drone strikes because they occurred in the alliance members' exclusive economic zones.
“It's a matter of discussion whether the exclusive economic zone is included in the Article 5-type reaction or not,” he said. “And it seems that until now, it isn't — which raised a lot of questions.”
NATO has been too slow to respond in the Black Sea, he argued.
“Tens of incidents are happening and Russia is getting closer to NATO borders. Words are not enough,” Mr. Tudor said.
A growing threat
The Black Sea drone incidents in October are just the latest in a long string of drone airspace incursions into Romania and other NATO members since Moscow launched its full-scale invasion of Ukraine. While most have come from Russia, Ukrainian drones have also crossed borders.
In August, Romania deployed two F-16 fighter jets to destroy a naval drone that was reportedly carrying explosives and was spotted near a major Black Sea gas project, a decision that Acting Defence Minister Miruta said was made to “protect the lives of the several hundred people” working on the gas platform.
A source in Romania's defence sector, who was not authorised to speak publicly about the incidents, told The Associated Press that the attacks are designed to hurt Ukraine economically and that “Romania is not the target right now.”
“All summer we've been hunting all kinds of (drone) debris, water drones, sea drones, air drones, debris in the water, on the beaches,” they said. “If this continues … someone should do something about that.”
Potential calls for an escort corridor
The source added that they have heard Turkey “would like to summon all the riparian (Black Sea) states to plan a mission to escort these convoys” through a militarised safe corridor.
“I'm not sure about Turkish, but our Romanian vessels don't have anti-air defence systems to protect against drones,” they said. “That would be a high risk for the Navy, for military vessels to escort this.”
In July, Romania, Bulgaria, and Turkey expanded the Black Sea Mine Countermeasures Task Force naval pact to “expand the missions to the protection of critical submarine infrastructure,” according to Romania's defence ministry.
It would include, it said, a permanent naval presence in Romania's exclusive economic zone.
Many commercial vessels are flagged to one country and owned by a company based elsewhere.
“Why would Romania and Turkey escort a ship from Bermuda with, I don't know, an Argentinian owner just to transport a few hundred tons of grains from Egypt?” the source said. “It's difficult.”
Bulgarian Defence Minister Dimitar Stoyanov said Wednesday that the country plans to join NATO's Drone Edge project by the end of October. Launched in July, the initiative — which Romania also joined — aims to invest over $40 billion in “counter-drone capabilities” over the next five years.
Cezar Gheorghe, founder of grain consultancy firm Agricolumn, told the AP that the drone incidents have not negatively impacted trade at Romania's Black Sea port of Constanta. The main concern is a rise in insurance costs in the wider Black Sea, he said.
“The [premium] for the risk is increasing, ... everyone who wants to come to Constanta, let's say from Turkey, from the Bosphorus Strait and across that area, will have a [premium] on insurance costs,” he said.
He added his main concern is a “serious incident” occurring at or near Constanta. In June, a Ukrainian maritime drone exploded at the port, and three others nearby.
“It's a matter of time,” he said.