Updated

France's highest court on Wednesday overruled a lower court's acquittal of five former inmates at the Guantanamo Bay prison and ordered an appeals court to rehear the case centering on terrorism charges.

The Court of Cassation did not immediately explain its reasons for the ruling, but a copy of its decision will be available Thursday, a spokesman for the court said.

The high court said a new appeals court panel will be created to handle the case, said the spokesman on condition of anonymity because he was not authorized to speak publicly on the matter.

A defense lawyer representing two of the men criticized the ruling, saying it amounted to a "sinister page in the history of the judicial system" and "a great cruelty on a human level."

France is among the few Western countries to prosecute nationals who have returned home from Guantanamo. The acquittal had been a high-profile foreign disavowal of the prison, which President Barack Obama wants to shut down.

The Paris criminal court in 2007 convicted the five — Ridouane Khalid, Brahim Yadel, Khaled ben Mustafa, Nizar Sassi and Mourad Benchellali — of "criminal association with a terrorist enterprise," a broad charge often used in terror cases in France.

During the original 2007 trial, the suspects had acknowledged having spent time in military training camps in Afghanistan, but said they had never put their combat skills to use.

But last February, a Paris appeals court ruled that agents from the French counterterrorism agency DST who questioned the five inmates at Guantanamo in 2002 and 2004 had overstepped their roles, and overturned the convictions. The court ruled that DST could not act as both a spy agency and a judicial police service, which questions detainees under French law.

The men, who were arrested in Afghanistan in 2001, each spent a total of 2.5 to 3 years in custody at Guantanamo and in France, to which they were repatriated in 2004 and 2005.

All seven French citizens who were at Guantanamo were sent home in 2004 and 2005. One was immediately released; another was acquitted in trial; the last five were convicted for roles in a terror group in Afghanistan.

The five were each sentenced to a year in prison. Because they had served more than that time before the trial, they did not return to prison after the sentencing.

William Bourdon, a lawyer for Sassi and Benchellali, called the court's ruling "a step backward for the state of law in France ... unfortunately, this is a rather sinister page in the history of the judicial system."

"For my clients, a third trial after all these lost years — notably 2 1/2 years at Guantanamo, for nothing — amounts to a great cruelty on a human level, and it's unbearable," he said. Asked how they responded to the decision Wednesday, he said simply: "Badly."

Bourdon said a new trial isn't likely to take place until at least next year, and that there is little likelihood that the former detainees will be ordered to return behind bars no matter what the final verdict is.