Foreign Minister Ine Eriksen Soreide, confirming the operation to bring them home, told reporters: "We are doing that for humanitarian reasons because we fear the child is sick."

The government had until now refused calls to bring back the five-year-old, who according to media reports may be suffering from cystic fibrosis, unless his mother let him travel alone.

But the right-wing administration relented, allowing the three to travel to Norway from the Kurd-controlled camp at Al-Hol, northeast Syria, where they have been detained since March 2019.

Norwegian daily Aftenpost published a photo of the 29-year-old veiled mother, taken they said as she crossed from Syria into Iraq with her two children and two men. All the faces in the photo were blurred out.

The mother, who is described as Pakistani, is accused of having travelled to Syria in 2013 and married a Norwegian jihadist who was killed in fighting.

She faces arrest when she gets to Norway on suspicion of belonging to a terrorist organisation.

Since the collapse of the Islamic State group's so-called caliphate, the international community has been grappling with the problem of what to do with captured foreign nationals who fought with them.

While Norway has acknowledged the rights of former jihadists to return home, it has until now refused to help them, except in the case of lone children.