Bulgaria's military aircraft will fly far more along the Black Sea coast and operate in its territorial waters, defence minister Dimitar Stoyanov told reporters at the Military Club in Sofia. The club hosted an event marking 145 years since the founding of the Vaptsarov Naval Academy.

On 18 October, Stoyanov told BNT that aircraft from a NATO member state would soon be based in Bulgaria, because attacks on ships in the Black Sea are becoming more frequent. By the end of the month, Bulgaria will send NATO a letter asking to join its programme for protection against drones.

Earlier on this story: Aircraft from NATO ally expected in Bulgaria after Black Sea attacks

The minister said the extra flights should not worry people, because monitoring of Bulgarian territorial waters has been stepped up.

The first flights of the new unmanned system took place the day before. Stoyanov stressed that Bulgaria's armed forces will operate it. He also mentioned the Poseidon reconnaissance aircraft.

Prime minister Rumen Radev said on 13 October that drones had again attacked ships in the Black Sea. Two ships were hit: one sank and the other was towed to the port of Burgas.

The Military Prosecutor's Office is leading a pre-trial investigation into the drone strike on the ship Chelsea 3. Experts are examining the ship and searching for fragments of unmanned aerial vehicles. Stoyanov noted that an explosion always leaves debris. Investigators still have to establish whether the pieces they found come from the ship, from a drone or from something else.