Around 15 Dutch women who joined IS forces during the Syrian civil war escaped from Kurdish detention camps in the past year, ministers have admitted.

Caretaker foreign affairs minister Sigrid Kaag and defence minister Ank Bijleveld told parliament that around 30 women with Dutch nationality were still being held by the Kurds.

Kurdish authorities have appealed to western countries to repatriate people who travelled to Syria to fight for IS or support the terrorist organisation, but many have been reluctant to do so.

Lawyers have also said the Netherlands should bring its citizens home to face justice because otherwise the courts could throw out the cases against them, leaving them free to return later.

Last year the Supreme Court said the Dutch state was not obliged to repatriate women who had travelled to the fighting in Syria or their children.

Kaag and Bijleveld said in a letter to MPs that they were concerned that the Kurdish authorities had lost track of the 15 women. They added that there were no reports of men escaping custody.

‘Escaped travellers could rejoin terrorist groups and then return to the Netherlands under the radar,’ the ministers said. All such individuals whose names are known have had their passports annulled, they added.