The ship Chelsea-3, hit by drones in the Black Sea, has been towed to the port of Burgas, Bulgaria's transport ministry said. It had drifted out of control off the Bulgarian coast for several days. See our original report: Drones hit two ships near Bulgarian waters, one sinks.

The operation began yesterday at about 10:30 under the ministry and the Burgas Maritime Administration. Zhivko Petrov was the captain. The navy and border police also took part.

Chelsea-3 lay 12.5 nautical miles south of Cape Maslen Nos and 10.7 nautical miles east of Lozenets. Its anchor had caught on the sea floor, which kept the ship steady and let the towing begin.

By 14:00 the tug Aliot and Chelsea-2, a second ship with the same owner, were alongside the damaged vessel. Crews then spent nearly seven hours on checks and preparation. At 20:55 the ships set off for Burgas.

"This was a rescue operation on the second attempt, and it was a success. We are extremely pleased," transport minister Georgi Peev said. He called the operation unprecedented and said it took place in bad weather.

Peev said the ministry did all it could to bring the ship to Burgas. "As the Ministry of Transport, we are responsible for making sure drifting ships are not left uncontrolled in our sea," he said.