Up to 750 European children trapped in north-east Syria

Another 200 are from the Netherlands, 160 from Belgium, and 60 are UK nationals.

The largest camp is known as Al-Hol and controlled by the Syrian Democratic Forces (SDF).

Some 70,000 people, the vast majority women and children, are trapped in the camp and forced to live in terrible conditions exasperated by the recent Turkish invasion.

Fears are now mounting that the window of opportunity for repatriating the children is closing as EU states grapple with the politics that underpin the actions of their parents.

Victims themselves, the children appear increasingly caught in a political tug-of-war between competing political interests of member states.

"If a child is a member state citizen, then their protection should prevail over any political concerns," said Belgium centre-left MEP Maria Arena, who chairs the European Parliament's sub-committee on human rights.

Politics aside, the numbers are significant. An estimated 28,000 children from more than 60 different countries remain trapped in north-east Syria.

Of those, less than 20 percent are 12 years or older, and half of them are under the age of five. Some 20,000 are Iraqis. The remaining 8,000 come from other countries of which up to 750 are from EU member states.

Bringing them home is rendered all the more difficult given the SDF forces won't allow the children to be repatriated without their mothers, who are often die hard Islamic State sympathisers.

It means governments are more likely to take in only orphaned children, a move so far made by only a handful of EU states.

Belgium over the summer took home six children, bringing its total to 30.

"The biggest threat for Europe is the threat coming from lone actors, those who were not there but lone actors who are here," pointed out Belgium's deputy attorney general Paul van Tigchelt, who also heads a Belgian threat analysis unit.

Commission stymied

The European Commission is pressing EU states to step up the repatriations but its role is limited given the national security prerogatives of EU states.

Instead, it is financing projects worth some €68m to help get food and shelter to people displaced by Turkey's military invasion into the territory.

"These projects are still underway despite the combat situation," said Michael Koehler, a senior European Commission official.

Similar comments were made by Christiane Hoehn from the EU's counter-terrorism coordinator's office.

"There is no EU policy on the repatriation of foreign terrorist fighters and family members in Syria and Iraq. The member states regard this as a national security issue," she said.

Other EU states are pressing to get their citizens tried in Iraq but critics say this will lead to unfair judgments and death sentences.

Seven EU states are discussing the possibility of a hybrid tribunal with Iraq, said Hoehn.

"The younger the children get repatriated, the better, the easy and the more likelier it is to have rehabilitate these traumatised children. The older these children get, the greater the risk they radicalise, the more difficult it will be reintegrate them," she said.