The MoD are investigating photos posted on Facebook which are thought to depict special forces serving on operations in the Middle East.
Posted last month, the photos are thought to show SAS soldiers on operations in Iraq.
Over 2,000 images, some of which show special forces on operations and during training, have been shared to a Facebook page.
It’s thought to be the first time pictures of the SAS working with dogs have ever been made public.
Other non-standard issue equipment is also pictured – including Colt Commando rifles.
An MOD spokesperson said: "We are aware of an incident involving soldiers sharing images online.
“We expect the highest standards of behaviour from our personnel at all times, whether on or off duty.
“If any action by service personnel are deemed to breach values and standards, they are treated very seriously and there are a number of sanctions available to the chain of command up to or including discharge."
It remains unclear whether the page is run by serving soldiers or not.