London: A father said on Monday he believed his son, a British medical student, was among a squad of Daesh militants filmed beheading Syrian soldiers in a video posted online on Sunday.

Ahmad Muthana told the Daily Mail newspaper his 20-year-old son Nasser Muthana appeared to be among a group of 16 militants who were seen on the video, which also showed the severed head of American hostage Peter Kassig.

“I cannot be certain, but it looks like my son,” said Ahmad Muthana, who lives in the Welsh capital city of Cardiff.

“He must fear Allah now for killing people. How can he expect to face Allah if he is killing human beings?” The announcement of aid worker Kassig’s death, the fifth such killing of a Western captive by Daesh, formed part of the 15-minute video which showed the beheadings of at least 14 men Daesh said were pilots and officers loyal to Syrian President Bashar Al Assad.

Daesh, which is fighting in Iraq and Syria, includes thousands of foreign combatants and has become a magnet for Islamist militant volunteers from Europe and North America, Western intelligence agencies have said.

French Interior Minister Bernard Cazeneuve said there was a strong likelihood that a 22-year-old French citizen also appeared in the beheading video.

The British Foreign office declined to comment.

Daesh has previously released videos of the beheading of two American and two British men which feature a masked, black-clad militant brandishing a knife and speaking with an English accent, who has been dubbed “Jihadi John” by British media.

Sunday’s video showed most of the killers unmasked and the Daily Mail said the man who appeared to be Nasser Muthana was standing alongside Jihadi John.

Nasser Muthana had already appeared in a online video released in June urging Muslims to join Daesh.

His younger brother Aseel had also travelled to Syria after both were radicalised in Cardiff, his father told the BBC in June. Nasser Muthana’s school friend Riyadh Khan also appeared in the online footage in June, various media reports said.