A chemical tanker has reported a suspected drone strike inside Romanian territorial waters — the first such attack to cross from the exclusive economic zones of Romania and Bulgaria into waters where NATO obligations are unambiguous.

The Comoros-flagged Yara J was anchored roughly 10 nautical miles southeast of Sulina on Wednesday evening when its crew reported an explosion and fire onboard. The ship was in ballast and preparing to enter the Danube. The crew put the fire out themselves. Nobody was hurt.

Romania's defence minister Radu Miruță said an investigation is underway. He stressed one point that matters for how this gets read in Brussels: military radar did not detect a drone approaching the vessel. The tanker heads to Constanța for inspection.

That radar gap is the mechanism worth watching. A strike inside territorial waters, on a vessel radar failed to track, is a different category of event from the incidents further offshore.

How the escalation has built

Wednesday's incident is the sixth reported drone attack on merchant shipping off Romania and Bulgaria since October 5. Three vessels have sunk. The Yara J, by contrast, survived and stayed operational.

Bulgarian prime minister Rumen Radev has suggested Russia sits behind the attacks, while acknowledging that definitive evidence is lacking. Moscow's ambassador to Sofia has floated the alternative that a third party was involved.

Meanwhile Russia's defence ministry claimed on Wednesday that its forces struck a dry cargo ship heading towards Odesa, followed this morning by claims against two more dry cargo vessels bound for the Ukrainian port, plus strikes on infrastructure at the Danube port of Izmail. The claims are unverified. The ships have not been identified.

Romania has scrambled fighter jets repeatedly after drone incursions near the Danube delta. Two aerial targets entered Romanian airspace on Wednesday evening; Ukrainian air defences destroyed one near Reni. At 01.34 this morning another drone was detected over Romanian territorial waters southeast of Sulina, prompting deployments of Spanish F-18s and Romanian F-16s.

What does this change for Black Sea operators?

Until now, shipowners and their insurers could treat the attacks as a risk of the EEZs — serious, but offshore. A strike inside territorial waters of a NATO member raises the stakes, because it forces allied governments to decide what constitutes an attack they must respond to.

For carriers and charterers on the Danube grain and cargo runs through Sulina and Izmail, the practical question is simpler: does the escort and surveillance net improve before another hull is lost? Three sinkings in under two weeks suggests the current risk assessment already trails events.

Regional response taking shape

Bulgaria is now working with Türkiye and Romania on an initiative to protect commercial shipping in the Black Sea, foreign minister Velislava Petrova-Chamova announced in Berlin yesterday.

"This is actually an initiative in which we should involve all our European partners. We all bear a common responsibility," she said.

Petrova-Chamova also outlined plans for a Black Sea Maritime Security Centre, with operations in Varna and Constanța, to tighten surveillance and protect critical infrastructure.

The centre would give operators a single point of monitoring across Bulgarian and Romanian waters — useful, if it closes the radar gap that let a drone reach a tanker inside territorial waters undetected. Whether the initiative draws in broader European participation, and how quickly the Varna and Constanța operations go live, will shape risk premia and routing decisions across the western Black Sea in the months ahead.