Trump's threat

That US President Donald Trump is extremely good at attracting global attention is a fact. The other day, he, for example, threatened to release Islamic State prisoners at European borders if France, Germany and other countries don' t take back their captured nationals. "I defeated the Caliphate, and now we have thousands of prisoners of war, ISIS fighters. We're asking the countries from which they came, from Europe, we're asking them to take back these prisoners of war. So far they've refused," Trump reportedly said, singling out Germany and France.
It is unlikely that Germany, France and others would take back their captured nationals anytime soon because of a variety of reasons. France, for example, has clearly declared that nothing will have any impact on its policies which determine the return of ISIS fighters on a 'case by case' basis. It is also unlikely that the US would release the ISIS fighters anytime soon; it will save them for a rainy day.