The Russian appointed governor Mikhail Razvozjayev describes the attack as "the most extensive attack" against the port of Sevastopol since the outbreak of the great war, TT reports with reference to AFP.
Razvozjayev also informed the residents of the Crimean Peninsula that images of what happened in the port must not be disseminated, as it risks revealing defense secrets.
According to the news agency, 16 drones were used in the attack.
Russian authorities claim that the Ukrainian unit behind the attack was trained by the British military.
Harbor entrance blocked
The Russian navy has blocked the port entrance to Sevastopol after the attacks and the port is to be closed to boat traffic.
Anton Gerashchenko, adviser at Ukraine's Ministry of the Interior, gives a completely different picture of what happened, AP reports.
He suggests that there has been "carelessness" in the handling of explosives aboard four Russian ships in Sevastopol port: among them a frigate, a landing craft and a ship that has been carrying cruise missiles.