UPDATE 1-Drone sinks ship off Bulgaria's Black Sea coast, prime minister says

(Corrects to remove "Ukrainian-owned" from headline and makes clear ​in second paragraph that the ​Ukrainian ship was damaged, not ‌sunk.) SOFIA, ​Oct 13 - Two ships were hit by drones off Bulgaria's Black Sea coast and one of ‌them sank, in the second such incident in a week, Prime Minister Rumen Radev said on Tuesday.

The Ukrainian-owned "Chelsea 3", sailing under Maltese flag, was hit by ‌three drones and damaged some 18 nautical miles (33 km) off the Bulgaria ‌coast around 1:30 a.m. (2230 GMT), Radev said. Its crew - seven Ukrainians and eight Azerbaijanis - had been rescued. Five crew members received medical assistance, but no one was seriously injured. One ⁠crew ​member of the ⁠sunken ship had also been rescued, Radev said.

"This is absolutely unacceptable — another attack in ⁠the immediate vicinity of Bulgarian territorial waters," Radev said in a televised address. "I am ​due to speak with NATO Secretary General Mark Rutte."

Radev said there ⁠was no clear evidence who carried out the attack but "the outcome benefits the Russian ⁠Federation", ​adding that he would summon the Russian ambassador about the incident. Bulgaria does not border either Ukraine or Russia, but as a NATO ⁠member it holds a strategic position on the Black Sea, where both countries ⁠have major ports. ⁠There are growing concerns about hybrid attacks involving drones by Russia as it wages war in Ukraine.