The tribunal courts said Wednesday they would not offer pre-trial release to former Khmer Rouge foreign minister Ieng Sary or former social affairs minister Ieng Thirith, his wife, following the arrest of the aging leaders Monday.

Tribunal spokesman Reach Sambath said the tribunal would not allow the couple to leave custody as a case is built for their trial, on charges of atrocity crimes.

Phat Pov Seang, Ieng Thirith's lawyer said he requested his clients be released, but the tribunal judges refused.

"We raised some reasons and concerns for our request, but they did not consider our reasons," he said. "According to the laws, we cannot say whether it is fair, but we are given a chance to file our complaints to the [pre-trial chamber for appeals]. So, we are going to try our best" to appeal.

Ang Udom, Ieng Sary's lawyer, said his client's arrest could lead to the loss of "important evidence" of Khmer Rouge crimes, if his health failed.

"We request he be freed. If he was detained temporarily, and he died for some reasons, we would lose important evidence regarding the killings of the regime," he said. "There is nothing wrong with the detention, but it is not beneficial. Just look at Ta Mok's case."

Khmer Rouge commander Ta Mok "the Butcher" died in Cambodian custody last year without seeing trial.