ISIS fighters are preparing to break extremists out of huge prison camps across Iraq and Syria, a new report has warned.

The Institute for the Study of War reported on Tuesday that ISIS wants to 'free its loyal fighters' and is using displacement camps to organize and raise funds.

It comes just days after US President Donald Trump, growing impatient at Europe's hesitance to take back its foreign fighters, warned that the US would release fanatics on European borders if countries refused to repatriate them.

Suspected Islamic State members seen inside a small room in a prison south of Mosul. There are an estimated 2,000 foreign ISIS fighters imprisoned in facilities across Iraq and Syria. President Donald Trump, left, said on Friday that he would release the prisoners on European borders if their countries failed to repatriate them

A foreign woman can be seen standing behind a wire fence at the al-Hol (Hawl) camp in northern Syria which houses relatives of ISIS. The camp is mainly populated by women and children who once lived under the rule of the so-called caliphate

The Hawl camp in Northern Syria, for example, houses 70,000 people - all of whom lived under the so-called caliphate.

Most of the people at the Hawl camp are women and children, displaced by the war.

There are an estimated 8,000 ISIS fighters imprisoned in Iraq and Syria with an additional 2,000 foreign fighters detained by US-allied Kurdish militias.

US Coordinator for counterterrorism, Nathan Sales, said that the US had seen a number of attempted break outs recently and that there is now more urgency for European nations to repatriate the foreign militants.

On Friday, US President Donald Trump said that Europe needed to take the foreign fighters back or he would give them back.

America has taken back eight of its own foreign fighters along with 13 children while many other European countries have refused to repatriate theirs. Nils D, pictured hiding his face during court, was returned to Germany and tried for torturing and murdering three people during his ISIS membership

Fighters with the US-backed, primarily Kurdish, Syrian Democratic Forces (SDF), stand guard as people queue at a scanning area for those who are evacuated from ISIS's embattled holdout of Baghouz earlier this year. Most of the foreign fighters are being held by Kurdish allies in Iraq and Syria but Trump has threatened to let them loose in Europe

'They mostly come out of Europe, and we've done them a tremendous favor ... So they have to make their decision. Otherwise, we're releasing them at the border,' he said to reporters at the Oval Office.

Sales refused to confirm whether Trump's plan of letting the fighters loose could actually be carried out.

'It's impossible to predict what tomorrow is going to look like in Syria, let alone two months or six months from now ... You could envision all sorts of other scenarios playing out,' Sales told ABC News.

'We don't want to assume that the relative stability that we see today is an enduring feature.'

The US has taken back eight of its own foreign fighters and 13 children. Six of the adults are now facing criminal charges.

Sales said that they would not take on any other countries' fighters and that it was their responsibility to deal with them.

The US has said that it is working to tighten the security at detention facilities but has called on European powers for additional funding and support.