The ship Chelsea 3, hit by three drones in the Black Sea, is in the port of Burgas with a badly damaged hull. There is no risk it will sink or pollute the water, said Capt. Zhivko Petrov, head of the Maritime Administration in Burgas. Who is behind the attack, and where the drones came from, is still unknown.

The ship had drifted without control for several days off the Bulgarian Black Sea coast. A tug began towing it on Friday at about 10:30am, and after a complex operation at sea, the tow ended in Burgas.

Inspections showed the hull is badly damaged in three places: at the front on the left, near the middle of the right side, and at the stern. The damage at the stern left the ship unable to steer. Petrov called it very lucky that the ship did not sink.

Over the weekend, bomb disposal experts, divers and military intelligence checked the ship for munitions and chemicals. They also inspected the underwater part of the hull. Investigators are looking for traces of the drones and working out how the strike happened. Access to the ship is restricted while the investigation goes on.

The drones are not Bulgarian, and everything else is speculation, Petrov said.

Chelsea 3 had earlier carried grain. It was empty when it was hit and was due to leave for a new cargo. It has valid insurance and the needed papers. The cost of the tow will be billed to the ship's owner or its insurer.

Officials will decide what repairs are needed once the investigation ends. For now, they assume the ship cannot sail as it is and will likely be repaired at a Bulgarian shipyard or ship repair yard.

Because the situation in the Black Sea has worsened, insurance for ships entering it is very expensive, Petrov explained. High premiums raise the price of the goods carried, and consumers end up paying.

Fewer ships now enter the port of Burgas, and some have cancelled planned visits, the Maritime Administration in Burgas said.