BRUSSELS — NATO allies will hold a crisis meeting to discuss how to respond to a series of drone strikes on cargo shipping in the Black Sea, Romania’s President Nicușor Dan said.

Two chemical tankers were hit by air drones in the past 24 hours in or near Romania’s territorial waters, but it is “too early” to say for sure whether Russia was behind the attacks, Dan added.

Dan was speaking on the sidelines of the European Council summit in Brussels, where he spoke to Bulgarian Prime Minister Rumen Radev and NATO Secretary-General Mark Rutte about the latest incidents.

“The secretary general expressed the solidarity of the alliance and there will be a NAC [North Atlantic Council] meeting at which the whole situation with the Black Sea will be discussed,” Dan told POLITICO. “Of course the conclusion is that all the hybrid attacks are trying to decrease our support for Ukraine. We will continue to support,” he said.

Dan said invoking NATO’s collective defense clause, Article 5, was “not now” being discussed as an option for responding to the attacks. Nor has Romania asked for Article 4 — the emergency clause that sets consultations in motion over military matters when a member’s security has been threatened — to be triggered, he said.

Rescuers are searching for seven missing crew members after two chemical tankers were hit by aerial drones in or near Romanian territorial waters. Over the past 10 days, drones have hit at least five more cargo ships close to Romania and Bulgaria — both NATO members — killing at least 23 sailors.

Investigation teams from Romania’s army and intelligence services are trying to establish what led to the most recent drones strikes on the ships, Dan said.

Romania asked NATO for equipment including specialized radars and requested the delivery to be accelerated after a Russian drone crashed into an apartment building near the border with Ukraine in May.

Dan suggested Romania was likely to seek further assistance with equipment from allies this time. “On the operational level, we are in the same situation where we have been … on the Danube border with Ukraine,” Dan said. “What we did at that moment, we came here to NATO and some of our allies — United States, France, Spain, Italy, Slovakia, Portugal — gave us some equipment. And now we are in the same situation, but on the other border, with the Black Sea.”

After the meeting with Dan and Radev, NATO’s Rutte said the alliance had already increased “counter-drone capabilities” along its eastern flank. “NATO will continue to work closely with our allies in the Black Sea, adjusting our deterrence and defence posture as needed,” he posted on X.

This story has been updated. Victor Jack contributed to the report.