The US has said it wants Britain and other allies to try their Islamic State jihadists captured on the battlefield, which could set them on a collision course over the fate of the two "Beatles". The US is urging the UK and other members of the coalition fighting Isil to help deal with the growing number of foreign fighters that are being held by Syrian Democratic Forces partners, saying the militants should be turned over to face justice in their home countries. The US-backed SDF is currently holding hundreds of foreign fighters, including Alexanda Kotey, 34, and El Shafee Elsheikh, 29, from London, and British-Canadian Muslim convert Jack Letts. "We're working with the coalition on foreign fighter detainees, and generally expect these detainees to return to their country of origin for disposition," said Kathryn Wheelbarger, a senior Pentagon official. British jihadi Alexanda Kotey "Defense ministers have the obligation and the opportunity to really explain to their other ministers or their other Cabinet officials just the importance to the mission, to the campaign, to make sure that there's an answer to this problem." The comment has been read as a direct response to Gavin Williamson, the Defence Secretary, who said last week that neither jihadist should be allowed home. “I don’t think they should ever set foot in this country again," he said. "They turned their back on Britain, our values and everything we stand for — they are the worst of the worst.” Tobias Ellwood, the defence minister, has suggested the government send the pair for trial at the International Criminal Court at The Hague. Jim Mattis, US Defense Secretary, is expected to press the issue during a meeting in Rome tomorrow with his European counterparts. The thorny subject of what to do with foreign Isil suspects has sparked intense debate in the West, with France saying they should be tried in situ by their captors. Alexanda Kotey, one of two Britons suspected of having been part of the Islamic State extremist group dubbed "The Beatles" who were captured by Kurdish militia fighters in January. Credit: ITV The pair, who are thought to have had their British citizenship stripped, were arrested last month by the SDF as they tried to flee across the Syrian border to Turkey among refugees. Together they make up half of an Isil cell commonly dubbed "The Beatles" because of the British accents, which tortured and beheaded Western hostages. US officials admitted that putting the two in the Guantanamo Bay, Cuba, detention facility is not an option. And British leaders have suggested they do not want the two men returned to to the UK. The legal issues are daunting. Most nations, including the US, would be unwilling to take back detainees unless they have the evidence to prosecute them, and that often is difficult to collect in such battlefield captures. The US could try to build a case around evidence gathered from Elsheikh and Kotey over the Beatles' torture and killing of American hostages James Foley, Peter Kassig and Steven Sotloff. The British have made no suggestion they plan to do so for the British victims, aid workers David Haines and Alan Henning. The Beatles If Washington fail to do so, the pair's fate becomes uncertain. The SDF has no internationally recognised legal status to try the suspects themselves and it is unclear what will happen to the hundreds of foreign suspects in their custody. An SDF official confirmed to the Telegraph that they are currently holding the men in northern Syria and have not yet received any extradition appeal. "Judging by the words of the British Defence Secretary I don't think the UK wants them back. He already said he wants all these fighters in Syria dead," Sherin Abdullah said. “We haven’t heard anything from Britain at all.” The commander of the SDF said on Monday that they were overwhelmed by the number of foreigners in their detention and “no one wants to take them back”. "The capacity problem is very real," Ms Wheelbarger said, noting that at one point the SDF was capturing as many as 40 militants a day. "Success in the campaign means you get more people off the battlefield. … These facilities are eventually going to be full." Elsheikh and Kotey are currently in SDF detention in northern Syria and have already been interrogated at length by the CIA. US officials have interviewed the men to extract intelligence about Isil's current operational capacity. They have also questioned them on the location of the burial sites of the Western hostages executed by fellow Beatle Mohammed Emwazi. The pair are understood to be talking and have offered some information that US commandos on the ground are now acting on.