Alexanda Kotey, 34, and El Shafee Elshiekh, 29, were two members of the notorious Isis execution cell – which included Mohammed “Jihadi John” Emwazi – who became known as “the Beatles” for their British accents.
They were captured by the US-backed Syrian Democratic Forces (SDF) last month while they were reportedly trying to flee over the Turkish border disguised as refugees.
The SDF said on Friday evening that they had not received a request from any foreign government to hand them over though officials from the US-led coalition fighting Isis in Syria did take part in questioning the terrorists.
It is also believed members of the CIA have been able to question them and members of the British intelligence services have had access to them.
Defence Secretary Gavin Williamson has already indicated that the UK will not oppose any attempt by the US to extradite them to face charges for the murders of at least 25 hostages – including David Haines and Alan Henning.
He said: “I don’t think they should ever set foot in this country again”.
But concerns have been raised after US President Donald Trump said he would keep the notorious prison camp open to house terrorists in his State of the Union address – despite his predecessor Barack Obama vowing to close it.
The UK is believed to strongly oppose the use of the facility, where detainees are held for years without trial in appalling conditions, and has already paid out £20m in compensation to UK citizens and residents who were held there after 9/11.
Now Defence Minister Tobias Ellwood has called for the pair to face international justice rather than imprisonment.
He told The Daily Telegraph: “We have robust rules of engagement which legitimise the killing of terrorists in theatres of operations, but once captured they must answer – and be judged [by] – to a legitimate authority.
“The horror of 9/11 meant we briefly lost sight of the standards and rule of law that took centuries to develop and fundamentally distinguish us from the terrorist.
“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”.