The Ukrainian military said that it successfully attacked and damaged a Russian warship as it was transiting inland waters on Saturday, October 4.
Ukrainian officials said the strike by personnel of the Special Operations Forces (SSO) targeted the Russian Navy Project 21631 or Buyan-M-class missile corvette Grad as it was en route from the Baltic Sea to the Caspian Sea via Lake Onega at around 04:31 local time on Saturday.
The attack took place in the Republic of Karelia, which is located approximately 960 kilometres north of the Ukrainian border.
The SSO said in a social media post that the ship suffered damage to its engine compartment, resulting in a loss of manoeuvrability and combat capability.
Grad is one of the newest Project 21631 ships in Russian Navy service, having been commissioned in late 2022. Its armament includes Kalibr cruise missiles.
Ukrainian officials said Saturday's strike on Grad was part of a broader offensive that also attacked other key targets within Russia, including an oil refinery 115 kilometres southeast of Saint Petersburg.