Romanian President Nicusor Dan accused Russia of escalating its attacks on NATO’s eastern flank on Friday, after a drone strike sank a cargo ship off the Romanian Black Sea coast, killing at least one sailor with three still missing.

Video released by Romanian authorities showed only a small part of the hull of the capsized tanker still visible above the waves as it sank. Emergency vessels were searching the surrounding waters for survivors in choppy seas and high wind.

Romania’s naval authority said the Comoros-flagged Khoryv, with a crew of 13 Ukrainian and Azeri sailors, had sent a distress signal 13 nautical miles off Romania’s port of Constanta, just beyond Romanian territorial waters. Nine sailors were rescued from the water, three were missing and one body was recovered.

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The past two weeks have seen a sudden surge in deadly attacks on commercial ships off the coasts of NATO members Romania and Bulgaria, with at least seven cargo ships hit and some 30 sailors reported dead or missing.

“It is part of Russia’s escalation process in its war in Ukraine,” President Dan told reporters, later saying the ship had been hit by a drone.

NATO said on Tuesday it would send more maritime patrol aircraft, radar systems and drones to the Black Sea. The alliance has not specified what capabilities would be sent. On Saturday, Romanian jetsshot down two of the latest generation of Russian drones over Romanian territorial waters.

The vessels that have been struck lately have either been anchored near or headed towards the Sulina Canal, which links the Danube River to the Black Sea.

The canal has become the primary export route for Ukraine, one of the world’s biggest grain and food oil exporters, which has relied on Danube River ports and Romanian territorial watersas Russia has attacked Ukraine’s own Black Sea ports.

Ukraine, Romania and Bulgaria have called on NATO to do more to protect commercial shipping in the Black Sea.

(Reporting by Luiza Ilie; editing by Peter Graff)

Related:

• Romania Blames Russia for Escalating Black Sea Ship Strikes
• Ukraine War Escalates as Black Sea Drone Strikes Hit Cargo Ships