Men, who the Democratic Forces of Syria fighters claimed were Islamic State fighters, walk as they are taken prisoners after SDF advanced in the southern rural area of Manbij, in Aleppo Governorate, Syria May 31, 2016. REUTERS/Rodi Said
FILE - Men who the Syrian Democratic Forces claimed were Islamic State fighters walk as they are taken prisoner after SDF advanced in the southern rural area of Manbij, in Aleppo Governorate, Syria, May 31, 2016.

U.S. President Donald Trump on Friday renewed threats to dump captured Islamic State fighters on Europe's doorstep if countries there continue to refuse to take back all their foreign fighters. 
 
Trump said he was continuing with plans to draw down forces in Syria, saying the U.S. had done the world a big favor by eliminating the terror group's self-declared caliphate and that it was time for other countries to step up. 
 
"We're asking them to take back these prisoners of war," Trump told reporters during a meeting with Australian Prime Minister Scott Morrison in the Oval Office at the White House. 
 
"They've refused," he added. "And at some point I'm going to have to say, 'I'm sorry, but you're either taking them back or we're going to let them go at your border.' " 
 
This is not the first time Trump has chastised Washington's European allies over the issue of IS foreign fighters. 
 
In February, after tweeting that the IS caliphate was "ready to fall," the president took allies to task over their reluctance to repatriate the captured fighters:

According to the latest U.S. estimates, the coalition-backed Syrian Democratic Forces are still holding more than 2,000 foreign fighters in makeshift prisons in northeastern Syria, along with thousands other IS fighters from Syria and Iraq. 
 
U.S. and SDF officials have warned that attempted jailbreaks have become common, as many of the facilities, designed to serve as temporary prisons, have been pushed to their limits. 
 
"This is not sustainable," Chris Maier, director of the Pentagon's Defeat IS Task Force, told reporters Wednesday at the Pentagon. "There are not prisons controlled by forces in northeast Syria that can house 10,000 ISIS fighters." 

But despite repeated calls by the U.S. and by the political wing of the SDF for countries to repatriate citizens and residents who left to fight for the terror group, the number of prisoners has remained fairly steady. 
 
"We ask for their countries to get them back. Nobody responds," Sinam Mohammed, the U.S. representative of the Syrian Democratic Council (SDC), said last week. 
 
Cuban facility

Some U.S. officials and lawmakers have floated the idea that some of the IS fighters could be moved to a facility like the one in Guantanamo Bay, Cuba, built after the Sept. 11, 2001, terror attacks to hold terrorists and fighters aligned with al-Qaida. 
 
But Trump on Friday rejected the idea. 
 
"The United States is not going to have thousands and thousands of people that we have captured stationed at Guantanamo Bay, held captive at Guantanamo Bay, for the next 50 years, and us spending billions and billions of dollars," he said. 
 
"They can try them, do whatever they want," the president said of the European countries. "If they don't take them back, we'll probably put them at the border and then they'll have to capture them again."