The Royal Navy has refused to deny that aircraft carrier HMS Prince of Wales encountered a Russian warship for the first time during training off the Scottish coast.
It comes after a report by Portsmouth News said the 65,000-tonne ship shared a sighting of a Russian training vessel on its official Twitter account.
They added that HMS Prince of Wales' post, made on Tuesday afternoon, was swiftly deleted by the Navy and with the News report quoting a source who claimed the tweet had been made "in error".
HMS Prince of Wales has been taking part in Exercise Joint Warrior 212, Europe's largest military exercise.
Portsmouth News claimed it is understood the Russian ship was shadowing the NATO fleet taking part in the training.
When approached by Forces News, a Royal Navy spokesperson refused to rule out that the incident had happened.
"HMS Prince of Wales is at sea taking part in Exercise Joint Warrior along with 27 ships from nine other NATO nations," the spokesperson said.
"During the exercise, the Royal Navy and NATO monitors and tracks nearby naval activity."
Watch: Amazing recent footage of Royal Navy Hawk aircraft flying over HMS Prince of Wales.
All three services of the UK Armed Forces and a number of NATO nations are taking part in Exercise Joint Warrior 212.
The £3.2bn HMS Prince of Wales is currently working towards being declared ready for frontline operations.
Recently, HMS Prince of Wales and her sister ship HMS Queen Elizabeth simultaneously launched F-35B fighter jets for the first time.
The Queen-Elizabeth class carriers are the biggest and most powerful vessels ever constructed for the Royal Navy.