The 16 Europeans were arrested on Thursday just before the flight was due to take off from the town, 700km east of the capital N'Djamena.
Ahmat Bachir, Chad's interior minister, said that if found guilty the charity workers would face up to 20 years in jail with hard labour.
A judicial source said they would be transferred to the capital N'Djamena "for reasons of security" and because Abeche had no proper court.Adoption
The charity workers have said that the children were 103 orphans from Sudan's war-torn Darfur province.
But the UN children's agency said after interviewing the children that most appeared to be Chadian and there was no evidence they were orphans.
|"They wanted to do things differently, that doesn't mean they wanted |
to do it dishonestly"
Gilbert Collard, lawyer for Zoe's Ark
The children, aged one to 10, were reportedly to be adopted or fostered by families who each paid up to $8,600, allegedly to cover evacuation costs.
They are currently being cared for at an orphanage in Abeche.
Idriss Deby, Chad's president, has promised "severe punishment" for what he has described as a "kidnapping" or "child trafficking".
He suggested that the group planned to sell the children to paedophiles or "kill them and remove their organs".
"These people ... treat us like animals. So this is the image of the saviour Europe, which gives lessons to our countries. This is the image of Europe which helps Africans," the official website of Chad's presidency quoted Deby as saying.
Nicolas Sarkozy, the French president, telephoned Deby on Sunday to denounce the planned airlift as "illegal and unacceptable".'Rescue' operation
Zoe's Ark has insisted that it mounted the "Children Rescue" operation in good faith, hoping to take a group of orphans away from Darfuri refugee camps in Chad to a better life in France.
It says it was given statements from tribal leaders that the children were orphans with no known relatives, and that the Chadian and French authorities had full knowledge of their activities.
|Charity workers from Zoe's Ark say that they |
were taking the children to a better life [AFP]
"We are dealing with humanitarian hardliners who walked off the beaten track," Gilbert Collard, a lawyer for Zoe's Ark, said in the southern French city of Marseille.
"They wanted to do things differently, that doesn't mean they wanted to do it dishonestly."
However, the French news agency CAPA released footage of interviews with members of Zoe's Ark in which one person said they could never be completely sure the children were orphans in need of help.
"We tried to verify as much as possible. We can never be sure, of course. We cannot be sure about this information," said one unidentified man who was among those arrested.
A reporter for French news agency CAPA was among the French nationals arrested.
The French government has said it warned Zoe's Ark months ago that it risked breaking the law if it carried out the operation.