Ukraine’s military says it attacked and destroyed a Russian submarine while it was anchored at a port in the occupied Crimean peninsula.

The Rostov-on-Don, a kilo-class attack submarine launched in 2014, sank after it was struck in a missile attack on the port city of Sevastopol on Friday, Ukraine’s general staff said in a statement.

It was reportedly one of four submarines operated by Russia’s Black Sea fleet capable of launching Kalibr cruise missiles. The Russian defence ministry has not commented.

Officials in Kyiv said the attack also destroyed four S-400 air defence systems protecting the peninsula, which Russia illegally annexed in 2014.