By Betel Miarom

N'DJAMENA, Oct 26 (Reuters) - Chadian President Idriss Deby vowed on Friday that nine French nationals detained for trying to smuggle out African children to live with European families would pay for their "horrible" crime.

Chadian police arrested the group on Thursday as they were preparing to fly 103 children, aged 3-8 and mainly from Sudan's conflict-torn Darfur region, out of the eastern Chadian city of Abeche on a French charter plane.

"It is a horrible act which I say is a crime. I strongly condemn it," Deby told reporters on Friday during a visit to a social centre in Abeche where the children are being cared for.

"All administrative and judicial steps will be taken so that these people and their accomplices pay for their actions. The Chadian and Sudanese authorities must from now on put in place control systems so this never happens again," he said.

The nine arrestees included the head of a group called Zoe's Ark, which said earlier this year it hoped to bring orphans from Darfur to France for adoption.

Chad's interior minister, Ahmat Mahamat Bachir, said on Thursday that some of the 103 children were Chadian, not all were orphans and the operation had no official authorisation.

The smuggling attempt also drew condemnation from French President Nicolas Sarkozy, whose spokesman said the Paris prosecutor's office had opened an inquiry on Wednesday into "illegal exercise of intermediary activities with the aim of adoption".

FOREIGN MINISTRY WARNING

The French Foreign Ministry issued a warning about Zoe's Ark in August, saying there was no guarantee the children were helpless orphans and casting doubt on the project's legality.

Around 300 families in France and Belgium had paid 2,800-6,000 euros ($4,000-8,600) per child to have them flown to an airport in Vatry, 120 km (75 miles) east of Paris, a French diplomat said on Thursday.

Families hoping to welcome the children waited in vain all night at Vatry airport.

Since the Foreign Ministry's warning, Zoe's Ark had stopped saying it aimed to have the children adopted, the diplomat said.

The organisation's Web site www.archedezoe.fr continues to say its plans to bring children from Darfur to Europe are justified by the Geneva Convention and international law.

"Everything was done with the agreement of the French government which has known about the operation since April," Agathe Deregnancourt of the "Group of families for the orphans of Darfur", an umbrella organisation which includes Zoe's Ark, said on French TV channel BFM TV.

"It's not a question of buying or adopting. (The children) should legally have a political refugee card to have the right of asylum in France ... and the families were volunteering to welcome these children into their homes," she said.

Rama Yade, France's secretary of state for foreign affairs and human rights, was contacted three months ago by Zoe's Ark, and had warned other government agencies of the "doubtful" nature of the plan, Sarkozy's office said.

"Taking children away like this is, from my point of view, illegal and irresponsible," Yade was quoted as saying in an interview published in Friday's Le Parisien newspaper. (Additional reporting by Anna Willard and Thierry Leveque in Paris)

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