Russian warships in the eastern Mediterranean Sea drove away a Dutch submarine shadowing the squadron, the Russian military has said.

Russian defence ministry spokesman Maj Gen Igor Konashenkov said two navy destroyers spotted the Walrus-class submarine on Wednesday while it was 20km (11 nautical miles) away from the Admiral Kuznetsov aircraft carrier and its escorting ships.

The destroyers had tracked the submarine for more than an hour, using anti-submarine helicopters, before forcing it to leave the area, Konashenkov said. He did not elaborate how the warships prompted the submarine to leave.

The spokesman added that such “clumsy” attempts to manoeuvre close to the Russian squadron could have resulted in an accident.

Konashenkov said the Russian squadron had previously spotted several Nato submarines, including a US Virginia-class nuclear submarine, while en route to eastern Mediterranean waters.

A Nato official said the alliance’s navies have been monitoring the Russian fleet in recent weeks in a “measured and responsible way, as is customary”. He refused to elaborate on how Nato was doing that.

In a tweet, the Dutch defence ministry said it does not comment on operations conducted by its submarines.

The Admiral Kuznetsov aircraft carrier is being accompanied by the nuclear-powered Peter the Great missile cruiser and several other ships on a mission to Syria’s shores, the Russian navy’s largest deployment since the 1991 collapse of the Soviet Union.

Nato has expressed concern, saying the move could presage an increase in the number of Russian air raids in Syria, particularly around the besieged city of Aleppo.