Russian Security Council Deputy Chairman Dmitry Medvedev described on Friday the United Kingdom as his country's "eternal enemy."

"Britain was, is, and will be our eternal enemy. In any case, until their arrogant and disgustingly damp island goes into the abyss of the sea from the wave created by the latest Russian weapons system," he wrote on his Telegram account.

Medvedev's comments came in response to the sanctions the UK imposed on several Russian individuals, which in turn were a reaction to a 25-year prison sentence given to political activist Vladimir Kara-Murza.