BBC News:
It was a dark night when the attack happened. Ukrainian drones were approaching fast through the water.
By the time the crew of the Russian patrol ship Sergey Kotov saw them, it was too late. Russian sailors opened fire with heavy machine guns, but their ship was hit and destroyed.
Ukrainian sea drones have revolutionised naval warfare over the last few years, relentlessly hunting down Russian ships in the open sea and even at naval bases.
Group-13, a secretive unit of Ukraine’s military intelligence agency, was behind the Sergey Kotov attack last week, and the BBC has been given rare access to its operations.
Since it was set up last year, the unit says it has sunk five Russian vessels and damaged others. But its commander, who asked us to refer to him by his call sign, Thirteenth, says the Sergey Kotov was the most difficult target so far.
Group-13 had attacked and damaged the ship twice in the past, but only managed to sink it on the third attempt.
