An unexploded wartime torpedo has been found in Scapa Flow in Orkney.
A Royal Navy bomb disposal team has been sent to the body of water, which was used as a base by the armed forces in both world wars.
HM Coastguard said the ordnance was found on the seabed during an underwater survey on Saturday.
An exclusion zone has been set up and warning signs erected with people being urged to stay at least 500 metres away from the area between Hoy and Cava.
Scapa Flow is popular with divers due to the British and German relics lying on the seabed.
The area is also the spot where more than 50 German war ships were deliberately sunk by their commander in 1919 to stop them being divided among the Allies.
A military Explosives Ordnance Disposal (EOD) team from Glasgow is currently at the scene and is expected to carry out an assessment to make the device safe.
Kaimes Beasley, duty controller for HM Coastguard said: "With weather in the area likely to be good today, it's more than possible that dive charter boats will want to go there, but our strong advice is to keep away."
Royal Navy bomb disposal experts were sent to the same area in 2016 to detonate a World War Two torpedo that was thought to have been fired at HMS Royal Oak by a German U-boat in 1939.
A total of 833 men were killed in the naval disaster.