Three boat drones struck and sank a vessel chartered by Israel’s ZIM Integrated Shipping Services off Bulgaria’s Black Sea coast Wednesday, forcing the evacuation of all 18 crew members as the ship went down with 421 containers aboard. 

The container ship had departed from Haifa port and was traveling to Constanta in Romania when it was attacked. ZIM said the crew was rescued and safely evacuated. 

Fourteen Filipinos and four Ukrainians were aboard the vessel. All were taken to the Bulgarian port of Varna following the attack. 

The ship sank with its entire cargo of 421 containers, including valuable goods and hazardous materials. Lithium-ion batteries, corrosive liquids and acids were among the materials aboard the vessel when it went down. 

Preliminary testing found no evidence of pollution from the sinking, according to the Bulgarian government. 

Bulgaria’s Chief of Defense, Adm. Emil Eftimov, said the country had been unable to destroy the unmanned vessels responsible for attacking the ship. 

Commercial shipping in the Black Sea has faced attacks involving unmanned aerial vehicles, or UAVs, and unmanned surface vehicles, including suicide boat drones, amid spillover from the ongoing Russia-Ukraine war. 

Several incidents involving commercial vessels have already occurred in the Black Sea, affecting Bulgaria, Romania, and Turkey.