"There are 364 children in 59 departments (areas in France), who are followed by judges for children, and who benefit from coordination from my office to make sure they have optimal care," Olivier Christen told the France Info radio station.

Another anti-terror prosecutor had in 2018 expressed fear that the children of French nationals who joined IS after it set up a so-called caliphate in 2014 could be "ticking time bombs".

But Christen, who leads the National Anti-Terror Prosecutor's Office (PNAT) opened in 2019 in the wake of a spate of jihadist attacks, brushed aside that worry.

"These 364 children in no way seem to me to correspond to that expression," he said.

"They are being closely monitored... They pose no particular difficulty."

"There are very different situations. Some are very, very young children, others are fully fledged teenagers," he added.

Overall 170 women had returned from Iraq and Syria to France, he said, including 57 from detention camps in northeast Syria in recent years since the IS caliphate's territorial collapse in 2019.

Of the 364 children who had been brought to France, "169 have been repatriated over the past two years," he added.

Until 2022, France only brought back children on a case-by-case basis, prioritising orphans and some children of women who had agreed to give up their parental rights. But Paris changed that policy two years ago.

IS seized control of large swathes of Syria and neighbouring Iraq in 2014, before Syrian forces spearheaded by Kurds and backed by a US-led coalition ousted them from their last patch of land in eastern Syria in 2019.

Kurdish autonomous authorities in northeast Syria have been holding around 56,000 people, including 30,000 children, in detention centres and camps.

Among them are IS fighters and their families, as well as displaced people who fled the fighting.