For the second time in a week, commercial ships have been attacked in the Black Sea off the Bulgarian coast, with one sinking, Bulgarian Prime Minister Rumen Radev said on Tuesday.

According to him, Ukrainian cargo ship Chelsea 3, sailing under the Maltese flag, was hit at around 1:30 a.m., 33 kilometers from the Bulgarian coast, near the town of Byala. Its crew reported being attacked by three drones. The seafarers—seven Ukrainians and eight Azerbaijanis—were rescued. Radev said that five crew members were provided with medical assistance, but there were no serious injuries.

As per preliminary data, another ship was attacked and sank 32 km from the Bulgarian village of Krapets.

According to Radev, only one seafarer was rescued from the sunken ship.

The Bulgarian premier noted in his video message that there are still no clear facts that would allow blaming any specific country for the attack, but added that “the result obtained is beneficial to the Russian Federation.”

Also, he said that the Russian ambassador to Bulgaria will be summoned to the foreign ministry in connection with this incident.

Just a week ago, unidentified drones sank a merchant ship off the coast of Bulgaria.

The Palauan-flagged cargo ship Able, which, although it caught fire, remained afloat, and the Togolese-flagged ship Alfa Watan, were hit.

The crew of the sunken ship are considered missing.