Graphic pictures which appear to show at least one UK serviceman posing with a dead Taliban fighter have been leaked online.
The Ministry of Defence said military police have launched an investigation into the photographs, which were taken after an attack by insurgents on Camp Bastion in 2012.
Two RAF Regiment members were withdrawn from frontline duties after the images were posted on website Live Leak in April.
They show some of the damage caused during the attack on the UK's main base in Afghanistan in September 2012, which left two US marines dead.
In two of the pictures at least one and possibly two members of the RAF Regiment can be seen kneeling next to the body of a dead insurgent and giving the thumbs up.
A number of British personnel were injured in the attack and six US Harrier jets were destroyed.
An RAF spokeswoman said: "Inappropriate actions will not be tolerated in the armed forces - the RAF is treating this incident extremely seriously and has launched a military police investigation.
"As this incident is subject to an ongoing investigation it would be inappropriate to comment further at this time."
The RAF Regiment is the ground fighting force of the Royal Air Force.
Members of No 51 Squadron RAF Regiment, together with US Marine service personnel and civilian security contractors, defeated the attackers after a four-hour firefight with support from helicopters in what came to be known as the Battle of Bastion.
Last month a report by MPs said British commanders had to "bear a degree of responsibility" for failing to prevent the 2012 raid.
Prince Harry was serving at the base as a member of the Army Air Corps during the time of the attack.