LONDON — A video showing British soldiers firing shots at a poster of Labour Party leader Jeremy Corbyn circulated on social media Wednesday, sparking widespread concern and an investigation by the Ministry of Defense.

Taking to Twitter, Sky News’s defense and security correspondent, Alistair Bunkall, shared the video, writing that the Defense Ministry had confirmed it as legitimate.

The British soldiers are believed to have been stationed in Afghanistan and at a shooting range in Kabul when the video was recorded and shared on Snapchat, before it was published to Twitter. Bunkall’s tweet of the footage had been viewed almost 900,000 times as of midday Wednesday in Britain.

The video, which opens with soldiers firing in succession, ends with a close-up of a bullet-riddled photo of Corbyn’s face.

“We are aware of a video circulating on social media,” the army said in a statement Wednesday. “This behavior is totally unacceptable and falls well below the high standards the army expects. A full investigation has been launched.”

For its part, Corbyn’s Labour Party described the incident as “alarming and unacceptable” and expressed full confidence in the Ministry of Defense to investigate it.

The video comes at a particularly tense time in Britain, as politicians continue to squabble and vote down Prime Minister Theresa May’s Brexit plans. This week, May and Corbyn will meet to negotiate how exactly Britain will leave the European Union — three years after a divisive referendum.

Calling the video “appalling,” Scotland’s first minister, Nicola Sturgeon, wrote on Twitter: “The MoD is right to launch a full investigation.”

Among those on social media voicing concern at the video’s content were lawmakers stunned by the footage. Jess Phillips, a Labour Party member of Parliament, tweeted: “This is absolutely hideous and irresponsible under this or any climate.”

Scottish Labour MP Paul Sweeney also expressed his disgust and called for an immediate apology. “This is disgraceful. It defies all the values and standards of the @BritishArmy soldier,” he tweeted.

“Our soldiers defend the nation and the queen [and] they should not get involved in politics,” said Rory Stewart, a former member of the British armed services, during a discussion with the BBC.