Ukrainian special forces caused “severe damage” to the Russian Baltic Fleet minesweeper Alexander Obukhov in a sabotage operation, Ukraine’s military intelligence (HUR) said.

The 890-ton, £200 million ship is based in the Russian coastal town of Baltiysk in the Kaliningrad exclave. It is said to have “suffered severe damage” due to water in its engine after “the mysterious appearance of a hole in a gas duct”.

If confirmed, this would be the second time Ukrainian special forces struck in Kaliningrad which is sandwiched between Poland and Lithuania around 250 miles from Ukraine‘s border.

On Telegram, the HUR added: ” Now the Russian minesweeper is undergoing major repairs, and this may be a serious problem – the damaged M-503 engine is a rare thing.

“Repairing a key installation on a ship is technically difficult and expensive.”