The Army is investigating footage circulating online which appears to show soldiers shooting a picture of Jeremy Corbyn .
The brief clip, 28 seconds long, is thought to have first been posted on Snapchat before being widely shared on Twitter .
It is not clear if the clip, which appears to have a filter, has been Photoshopped or manipulated.
Labour MP Jo Cox was shot and killed less than three years ago.
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According to Sky News the laughing and joking soldiers, firing simulated paint rounds, are at a shooting range in Kabul.
A senior defence source told the broadcaster: "This is a terrible look".
The Army said they were aware of the video and branded the behaviour 'totally unacceptable'. It says a full investigation has been launched, the Mirror reports.
Soldiers are supposed to be politically neutral.
There are some suggestions on twitter that the video is fake.
But Sky said the Ministry of Defence has confirmed its legitimate.
Tory MP Tom Tugendhat tweeted: "This is disgraceful and falls far below the standards expected of British Army soldiers."
The clip shows the four uniformed men pull out their weapons and fire repeatedly into the distance.
Some online have claimed the unknown troops belong to the Parachute Regiment.
After they finish shooting, the video pans around to reveal a huge target of the Labour leader.
As it zooms in, at least fifteen shots can be seen peppered across his face.
The video includes the caption "Happy with that."
The gun range is used to train “guardian angels” - the soldiers who stand guard on comrades conducting training with Afghan forces.
It was brought in after a number of deadly insider attacks on British troops.
Despite doubts about its authenticity the clip has drawn wide criticism on social media, with one person dubbing the video "fascist."
Others said that the unknown troops - whose faces can be seen in the footage - belong to the Parachute Regiment.
Jade wrote: "Extremely fascist behaviour but okay."
Anders Gardberg said: "How deeply unprofessional.
"The task of any military unit in a democratic country is to defend the nation and its institutions, not even target them as a joke."
Zach Martin posted: "Almost certain this is illegal but even if it isn't against the law for uniformed military personnel to threaten death [on] a Member of Parliament, it's undeniably f ** terrifying.
"Gentle reminder that Jo Cox was murdered by a "British Patriot" less than three years go."
An Army spokesperson said. “We are aware of a video circulating on social media, this behaviour is totally unacceptable and falls well below the high standards the Army expects, a full investigation has been launched.”
