Under the operation, which is the biggest in its kind since the defeat of Daesh two years ago, six mothers and 10 children were brought from Syria's Roj camp and have been taken into custody on their arrival to Belgium.
Ten Belgian children and six mothers have been recovered from a prison camp for captured extremists in Syria and flown home to Belgium, the government said.
The operation was the biggest such repatriation since the battlefield defeat of the Daesh group in 2019, and follows Belgium's decision to secure the return of under-12s.
The adult mothers were taken into custody on their return to Belgium late on Friday, and child protection authorities will interview the minors and assign them to social services.
"The priority has always been to get the children to safety. All the operations were carried out according to the pre-established plan," Prime Minister Alexander de Croo said.
The premier thanked Belgian officials, the Iraqi authorities and the Kurdish regional government.
Belgian Prime Minister had announced last March that Belgium would repatriate Belgian children and some mothers. It looks like it will be 6 women and 10 children. Important step! But this also means leaving behind about 15 women and 25+ children... https://t.co/P9j9UsAOVL— Thomas Renard (@tom_renard) July 16, 2021
'Matter of national security'
The group is from the camp in Roj, in northeast Syria, where surviving suspected members of the group are being held under the supervision of PKK-linked YPG terror group.
The YPG is the Syrian branch of the PKK, which Turkey, the US and the EU designate as a terrorist group.
The PKK has waged a terror campaign against Turkey and its neighbours for over 30 years and the fighting has left more than 40,000 dead, including civilians.
However, Washington has chosen the group as an ally to fight against Daesh in Syria despite Ankara’s protest, sweeping the links between the PKK and the YPG under the rug.
After the defeat of the Daesh terror group, territories it formerly held are now controlled by PKK-affiliated groups.
Hundreds of volunteer fighters from Europe travelled to Syria and Iraq during the Daesh group's campaign.
Many died, but others, including women and children, are trapped in camps.
Their presence has proven an embarrassment for many European governments, reluctant to allow citizens with suspected extremist ties to return to their homelands.
But de Croo announced in March that his country would do what it could to secure the return of the youngest, describing it as a matter of national security.
Belgium's extremism monitoring agency OCAM says mothers and children who have spent time in the camps need to be kept under watch, which is easier if they are on Belgian soil.
Heidi De Pauw, of the Child Focus NGO, praised the "courage" of the Belgian government and said she was happy the children had been able to "leave the dangers of these war zones".
"We hope that they will be able to live out their childhood anonymously and that their rights as children, such as access to education and health care, will be respected," she said.
The effort to recover the group took place in several stages and began in June, when a consular mission went to Roj to collect blood samples to verify the parentage of the children and their Belgian nationality.
For security reasons, it was not possible to visit the larger Al Hol camp where many foreign fighters are still present.
Belgium, along with France, is among the European countries that saw the largest number of foreign fighters leave after the outbreak of the war in Syria in 2011.
From 2012 onwards, more than 400 Belgians left to fight in the ranks of extremist organisations.
These returns could only be organised in small numbers over the last two years since the defeat of the Daesh.
Earlier this year, Belgian researchers estimated that about 40 Belgian minors were still in Syria.