The number of suspected foreign ISIS fighters being detained by US-backed forces in Syria has now surpassed 2,000, with a small number claiming to be US citizens, three US officials told CNN.

A Bosnian national suspected of fighting for Islamic State in Syria has been transferred to Bosnia and put in detention, the Balkan country’s prosecutor’s office said on Saturday.

The authorities in Kosovo said on Saturday that more than 100 of their citizens, mostly women and children who were relatives of jihadists, had been flown home from Syria under heavy security with the assistance of the United States.