Belgium has sent a team of officials to camps in Syria holding the families of ISIS fighters, with a view to return them to their homelands, amid mounting international pressure.
It announced on Monday that it had sent a consular mission to assess the number of its citizens still living in the camps.
The data will then be analysed and repatriation to Belgium will be considered, the Het Laatste Nieuws paper reported. The northern European nation repatriated six mothers and 10 children from the camps last year.
The newspaper said the current team have taken DNA samples to check whether the children have Belgian parents and interviewed their mothers to see if they would still want them to travel to Belgium, even if they did not meet the repatriation criteria.
Prof Gerrit Loots, who is involved in the missions, told the newspaper the team found 10 women and 21 children in the camps.
He said repatriation was “desperately needed” as radicalisation was taking place in the camps.
But Belgian MP Koen Metsu described the move as "madness" and said the previous repatriations had cost €1.7m ($1.79m).
"Less than a year ago, six ISIS terrorists were repatriated," he tweeted.
"Now only two left under lock and key. Why is the government making this costly, unforgivable mistake a second time?"
Last year Belgium's Prime Minister Alexander de Croo gave a warning that Syrian camps could be a breeding ground for the "terrorists of tomorrow".