Secretary of State Mike Pompeo promised allies Thursday that the United States would keep up the fight against ISIS but said European and other members of the international coalition fighting the terrorist group must take back and prosecute their nationals detained in Iraq and Syria to help keep the organization from regaining territory. Pompeo told foreign ministers and senior officials from some 30 coalition members that it’s imperative that they hold thousands of detained foreign fighters accountable for atrocities committed while ISIS held swaths of territory in the two countries. Many detained foreign militants are from Europe. Pompeo said bringing them to justice is critical to preventing ISIS from resurfacing and exporting its ideology. “That work begins with carrying out justice against those who deserve it,” he said. “Coalition members must take back the thousands of foreign terrorist fighters in custody and impose accountability for the atrocities they have perpetrated.” But allies such as France and Britain have little desire to see homegrown extremists who have caused mayhem through grisly attacks on civilian targets. France instead has been working with neighboring Iraq in hopes that it can prosecute foreign militants. A meeting Thursday in Washington of members of the coalition came amid concerns about the US commitment to the fight against ISIS remnants. Those concerns have increased as President Donald Trump has pressed to withdraw American troops from Syria. Pompeo dismissed those concerns and said the US would continue to lead the coalition. “Ask them if there’s a deficit of American leadership in fighting ISIS,” he said, pointing out that the US still has forces in Syria despite the recent Turkish invasion. Those troops, he said, will allow the US to retain the ability to launch airstrikes on ISIS targets and protect oil fields that the militants had once used to bring in significant revenue. Pompeo also urged coalition participants to step up funding for UN relief and reconstruction projects in Iraq and Syria to allow for the return of millions of civilians displaced by years of conflict. As the effort in Iraq and Syria goes on, Pompeo said it will also be critical to keep ISIS from expanding its reach to other areas, notably the Sahel region in west Africa where he said the group “is outpacing the ability of regional governments and international partners to address the threat.” “The fight against ISIS is a long-term test of will, a test of civilization against barbarism,” he said. “We know where we stand. Let’s work together to make sure our enemy does too.”