Drone strikes bring Black Sea shipping risk closer to NATO waters

Bulgaria urges caution on attribution

Ukrainian President Volodymyr Zelenskyy blamed Russia for the attacks off Bulgaria, saying Ukraine had conducted no operations in the area. He described the incident as a combined maritime and aerial drone attack intended to make the western Black Sea unsafe for navigation.⁵

Sofia was more cautious. Bulgarian Prime Minister Rumen Radev called the attack on the two merchant ships “absolutely unacceptable,” but said the origin of the drones had not yet been determined. He warned against political speculation while the investigation continued.³⁴ Bulgaria raised the matter with the European Union and NATO, according to the government.⁴

The distinction matters. An exclusive economic zone is not the same as sovereign territory. Under international maritime law, coastal states have economic rights in an EEZ, including over resources, but the waters remain outside territorial seas.

That makes the political response more complex for NATO members. A strike in an EEZ can be treated as a serious maritime security incident without automatically being framed as an armed attack on alliance territory.

NATO’s response problem

The attacks put NATO’s Black Sea members — Bulgaria, Romania and Turkey — in a difficult position. They need to protect navigation and reassure commercial operators, while also avoiding escalation if evidence remains incomplete or if the incident occurred outside territorial waters.

Insurance Journal, citing Bloomberg, reported that the attacks did not trigger NATO collective-defense clauses in Sofia’s view. It also noted the risk to shipping and alternative export routes through Bulgaria and Romania.⁷

That points to a likely response focused on surveillance, mine countermeasures, intelligence sharing, naval patrol coordination and diplomatic pressure rather than an immediate collective-defense posture.

The European Commission’s Oct. 7 midday briefing agenda included questions on the attacks on Bulgarian ships, the Black Sea Strategy, Romania and Bulgaria, showing that the incidents had quickly entered the EU’s security and transport-policy debate.⁹

Shipping and insurance costs rise with uncertainty

For shipowners, the central issue is less whether a strike is formally classified as an attack on NATO and more whether vessels can move safely through the western Black Sea at a predictable cost.

Maritime security firm Ambrey assessed that three merchant vessels had been hit in Romanian and Bulgarian exclusive economic zones within 24 hours and said Russian forces were highly likely responsible.⁶ Ambrey also warned that NATO-member EEZs should no longer be treated as safe by default, a judgment likely to influence routing decisions, war-risk premiums and chartering terms.⁶

War-risk insurance was already a defining cost for ships calling at Ukrainian ports or sailing near contested waters. The latest strikes threaten to expand that risk premium into routes that had been treated as safer alternatives, including corridors linked to Romania and Bulgaria.⁷

Higher premiums can make voyages uneconomic, narrow the pool of willing shipowners and increase the cost of moving grain, oilseeds and other bulk cargoes out of the region.

Commercial vessels become strategic targets

The strikes fit a broader escalation in the drone war. The Associated Press reported the same day that Russia said it had downed nearly 900 Ukrainian drones, while Ukraine faced renewed Russian drone attacks, including the strike on the Marshall Islands-flagged ship near Odesa.²

That tempo has widened the war’s operational space. Long-range aerial drones, uncrewed surface vessels and electronic targeting systems allow both sides to threaten infrastructure and logistics far from the front line.

In the Black Sea, the result is a gray zone in which commercial vessels may be struck, threatened or misidentified even when operating outside Ukrainian territorial waters.

For European security officials, the risk is not only that another ship will be hit. It is that a pattern of attacks in or near NATO-member maritime zones could normalize violence against commercial shipping without crossing a clear treaty threshold.

That would leave governments to manage a widening maritime security crisis through law enforcement, diplomacy, naval presence and insurance markets — rather than through the alliance’s most formal defense mechanisms.