A decision by British soldiers to shoot at an image of Labour leader Jeremy Corbyn was a "serious error of judgment", a senior military commander has said.
Footage captured in Kabul, Afghanistan, shows personnel from 3rd Battalion, Parachute Regiment using a picture of Mr Corbyn for target practice on a Simunition range.
Brigadier Nick Perry, commander of 16 Air Assault Brigade, said the army is conducting a full investigation and wants to get to the bottom of what happened.
"This is a serious error of judgment," Brig Perry said. "Let me be clear - the army is, and always will be, an apolitical organisation.
"We have 400 soldiers from the brigade conducting force protection in Afghanistan, and working closely with both Nato and Afghan partners. These soldiers are doing an outstanding job out there."
Mr Corbyn said: "I'm shocked, obviously, that this sort of thing has happened.
"I hope the Ministry of Defence will conduct an inquiry into it and find out what was going on and who did that."
There was no immediate response from the Defence Secretary, Gavin Williamson, as an army spokesman said they are aware of the clip 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," he added.
The video shows a number of soldiers taking aim down the range and firing their weapons - the camera then focuses on the target and zooms in on an image of Mr Corbyn.
With a graphic of "happy with that" across the screen throughout, a number of marks can be seen peppered across Mr Corbyn's face.
It is understood it was a non-lethal hardened wax substance aimed and fired at the image instead of metal bullets, with the incident taking place in the past few days.
The range is designed for and used by personnel to practise what is called the "guardian angel drill" - a force protection tactic.
Prime Minister Theresa May's official spokesman said the incident was "clearly unacceptable", and that she was aware of the video's content but had not seen it.
Commons speaker John Bercow also condemned the footage and said he would be "horrified" if service personnel behaved in such a way towards an MP.