Five years after the Islamic State group was driven out of its last bastion in Syria, tens of thousands of the jihadists' family members, including from Western countries, remain in detention camps run by the Kurdish autonomous forces in north and northeast Syria.

The Kurdish administration said in a statement that it had "handed over a woman and three children to the United Kingdom", following a meeting with a British delegation led by the UK's Syria envoy Ann Snow.

A source within the administration meanwhile told AFP that the four had been residents of the Roj camp where jihadists' relatives are held.

On May 7, the United States announced it had brought back 11 Americans including five minors, as well as a nine-year-old non-US sibling of an American, from IS prison camps in northeastern Syria.

The United States in the same operation facilitated the repatriation of six Canadian citizens, four Dutch citizens and one Finnish citizen, eight of them children, Secretary of state Antony Blinken said.

And in December, the Kurdish administration handed over to Britain a woman and five children who had also been residents of a jihadist camp.

Despite repeated appeals by local authorities, a number of Western countries have refused to take back their citizens from the camps.

Among the most high profile cases is that of Shamima Begum, a former Briton stripped of her citizenship after leaving the country aged 15 to marry an Islamic State fighter.