Rescued crew from the cargo ship "ABLE" have given different accounts of the blast that set the ship on fire last night in Bulgaria's exclusive economic zone. Some crew members spoke of sea drones, while another sailor said there had been an underwater bomb.

The blast happened about 70 nautical miles east of Byala. Two sailors were hurt and are being treated in Varna.

Asked whether drones were involved, one sailor said it wasn't a drone and that the blast came from under the water. Another crew member said the drone came from below, a third said sea drones hit them, and a fourth denied the ship was hit by any unmanned aircraft.

A Turkish sailor on the crew thinks the Russians dropped an underwater bomb that sparked the fire. He believes the bomb was Russian because the ship was carrying Ukrainian cargo.

Another crew member said they hadn't been warned of the strike, and one of the rescued sailors thanked Bulgaria.

The sailor's description of a hit "from below" was his answer to a question about drones. The term "drone" also covers naval unmanned craft, many of which move underwater, so the claim of an underwater bomb — in other words a sea mine — hasn't been confirmed.

A false-flag attack hasn't been ruled out.

The search goes on for 18 crew members from the second ship, "ALFA WATAN". Hopes of finding them alive are fading.