The future of the final two suspected members of an Islamic State execution group dubbed “The Beatles” hangs in the balance following their capture in Syria.

Britons Alexanda Kotey and El Shafee Elsheikh are under guard in the caliphate’s former heartland having fallen into the hands of Kurdish militia fighters in January.

It remains unclear who will determine the pair’s fate, with a US Department of Defence (DoD) spokesman saying they were “still considering options”.

The Home Office refused to comment on reports that both men had been stripped of their British citizenship, but Defence Secretary Gavin Williamson told The Sun he did not want to see the pair prosecuted in the UK.

Defence minister Tobias Ellwood called for their trial to be held at an international war crimes court.

Jihadi John became one of the most infamous Islamist killers of recent times (PA)
Jihadi John became one of the most infamous Islamist killers of recent times (PA)

He told the Daily Telegraph: “Given the scale of foreign fighters we should consider an agreed international process involving The Hague, which ensures terrorists from any origin are transparently and fairly held account for their actions.”

ITV News has obtained what they described as the first image of Kotey – wearing a grey top and with a dark beard – in detention after he allegedly tried to smuggle himself into Turkey to escape capture.

Along with Mohammed Emwazi – the killer nicknamed Jihadi John – and Aine Davis, they are thought to have been part of a group named after the ’60s band because of their English accents.

The four Londoners were linked to a string of hostage murders in Iraq and Syria during the bloody Islamist uprising and gained global notoriety.

US officials said Kotey and Elsheikh “are suspected to have participated in the detention, exploitation and execution of Western detainees”.

Asked if they would be prosecuted and, if so, where they might face trial, Major Adrian Rankine-Galloway from the DoD told the Press Association: “We are still considering options regarding el-Sheikh and Kotey, but rest assured our intention is to hold anyone accountable who commits acts like those they are alleged to have committed.”

He said US Government agencies are working closely with coalition partners “on the disposition of detainees in SDF detention”.

He confirmed they are being held by US-backed Syrian Democratic Forces (SDF) in a “detention location” in Syria, but said he could not give any further information.

The family of Elsheikh said in a statement that it had received no official confirmation of his capture.

It said: “If, as is being reported, our son is being detained, we as a family ask that any process be proper and fair.

“We understand that call indeed reflects what is asked for by the families of victims of ISIS and not one that reproduces the wrongs and atrocities committed by that organisation.

“We do not condone any acts against humanity whether perpetrated by hate, revenge or fear.

“We also convey our sympathy with victims and their families and those affected by these acts.”

The family said they would not be making any further statement.

There have been various reports as to where exactly they were captured.

Mark Campbell, co-chairman of the Kurdish Solidarity Campaign, said he understood from sources in the YPG (Kurdistan People’s Protection Units) the arrests had taken place in the Deir ez-Zur region in the north-east of Syria, towards the Iraq border.

An SDF statement on Friday said Kotey was captured around 90 miles from there in a rural part of Raqqa.

A spokesman said it is believed Kotey had been trying to cross into Turkey.

Alan Henning memorial garden
Alan Henning died at the hands of Islamic State (Family Handout/PA)

Emwazi, who was killed in a US air strike in 2015, appeared in a number of videos in which captives including British aid workers David Haines and Alan Henning were beheaded.

The fourth member, Davis, was convicted of being a member of a terrorist organisation and jailed for seven-and-a-half years at a court in Silivri, Turkey, in May 2017.

The Foreign Office said it did not comment on individual cases or ongoing investigations.