Belgium repatriated on Friday ten Belgian children of jihadist fighters and six mothers from Syria, the federal prosecutor said in a statement.

"A plane chartered by the Belgian Government landed yesterday at 21.20h at the military airport of Melsbroek," the statement read.

"Onboard were 6 Belgian women and 10 children coming directly from the Al Roj camp, located in the North-East of Syria" "

It is the largest operation of this kind organised by Belgian authorities since the fall of the so-called Islamic State group in 2019.

The adult women, "who were repatriated at their request," were arrested upon arrival, the federal prosecutor said.

"They were transferred to different prisons after having been given the opportunity to separate from their children in good conditions," the statement read.

Five of them were already sentenced in absentia to prison terms by Belgium courts for participation in the activities of a terrorist group. The sixth is under an arrest warrant for the same offence.

The women are the mothers of the repatriated children, who are aged between 8 and 2.

"First, the physical and psychological health of these children, who have been living in difficult conditions in Syria for a long time, will be checked in a hospital," the statement read.

"Then, an appropriate framework will be put in place on a case-by-case basis. The families concerned have been personally informed of the return of their relatives after the plane took off from Erbil."

Prime Minister Alexander De Croo hailed the success of the operation on Saturday and thanked Iraqi, Kurdish and local northeastern Syrian authorities for their cooperation.

"All operations went according to the pre-established plan," De Croo said in a statement.

"The priority has always been to keep children safe," he insisted.

In March, Prime Minister Alexander De Croo pledged he would "do everything" to repatriate children under 12 years old.

He emphasised the need to take into account the "well-being" of these children amid a deteriorating humanitarian and security situation in the camps in northeastern Syria.

It is also a matter of "security" for Belgium, said De Croo. Belgium's anti-terrorism authorities say it is much easier to monitor returnees when they are on Belgian soil.

More than 400 Belgians joined the ranks of jihadist organisations after the Syrian civil war broke out in 2011 -- among the largest numbers in Europe, along with France.

Belgian researchers estimated in a study published earlier this year that around 40 Belgian minors still remained in Syria.

Many European governments have been reluctant to take back their often radicalised citizens after IS was militarily defeated.

France's policy, for instance, is to repatriate French children, while their parents are left in Syria to face local justice.