The government’s counter-extremism tsar, Sara Khan, has criticised the far-right activist Tommy Robinson for posing for a photograph alongside military figures, saying his “attention-seeking is cover for divisive anti-Muslim hatred”.

The army is investigating after the former English Defence League leader posted an image of himself surrounded by a group of grinning young men in camouflage uniform, apparently soldiers or cadets.

Khan, the lead commissioner for countering extremism, who is overseeing a study of extremism across England and Wales, said: “This is typical of the far right. They manipulate and exploit their way into the mainstream, often targeting the military and co-opting its symbols.

“But Tommy Robinson’s attention-seeking is cover for divisive anti-Muslim hatred that is causing real harm to individuals, communities and society in general. We have to call it out. Muslims are proudly and selflessly serving in the armed forces, and the army’s decisive response is to be praised.

“I am very worried about the growing impact of the far right in England and Wales. We have to strengthen our response across society.

“Firstly, we need to better understand the scale, the tactics and objectives and the harms of the far right. That is why my commission has confirmed that we will bring in academics and frontline practitioners to review the threat of the far right in England and Wales.”

Robinson also posted a video of himself on Monday with a crowd who started cheering and shouting his name. He wrote on Facebook: “A moment like this makes it all worth while. Today I met real British heroes.”

The army said it was aware of the photograph and footage, and was “investigating the circumstances surrounding this”. A spokeswoman said: “Far-right ideology is completely at odds with the values and ethos of the armed forces. The armed forces have robust measures in place to ensure those exhibiting extremist views are neither tolerated nor permitted to serve.”

Imam Asim Hafiz, an Islamic religious adviser to the armed forces, said: “Any form of racism, discrimination or extremism is taken extremely seriously and will be dealt with accordingly. The armed forces remain absolutely committed to welcoming individuals from across all faiths and cultures into its ranks.”

The Muslim Council of Britain said Robinson “does not represent our armed forces, however much he tries to claim otherwise”.

“He will rile against the very real steps taken to make the military more diverse,” a spokesman added. “He will remain silent on the sacrifices Muslims and others made in the two world wars. We welcome the swift statement by the army in disassociating itself from the far right and we hope that safeguards are put in place to ensure that Islamophobia will have no place in our armed forces.”