A former French prime minister was ordered Tuesday to stand trial over a political smear campaign against Nicolas Sarkozy before he became France's president, a French judicial official said.

Investigating judges honored a prosecutor's request by ordering the conservative Dominique de Villepin to stand trial in criminal court on charges of "complicity in slanderous denunciations," the official said on condition of anonymity.

Villepin has vigorously denied the charges. He could face up to five years in prison if convicted. Four other suspected accomplices were also ordered to stand trial.

Unlike the others, Villepin can appeal the judges' ruling — but only if he chooses to argue the alleged wrongdoing was conducted as part of his official duties. He was serving as foreign minister at the time of the alleged crimes.

An e-mail received by The Associated Press from an e-mail address bearing Villepin's name said: "Nothing justifies this referral decision (to the court)."

"Throughout the investigation, the truth of facts and law have been diverted to the benefit of only one civil party to the case who is today at the same time the president," the e-mail said.

The e-mail's authenticity could not be immediately verified.

The judicial investigation hinged on the role Villepin allegedly had in spreading phony allegations in 2004 that then-government minister Sarkozy and other top figures had secret bank accounts for laundering bribes. At the time, Villepin and Sarkozy, considered rivals, were both seen as leading contenders for the presidency in 2007, though Villepin never ran.

The scandal broke when a judge received an anonymously sent computer disc that accused Sarkozy and other top officials of using Luxembourg bank Clearstream to hide kickbacks from the sale of French frigates to Taiwan in 1991.

The charges proved baseless and investigators turned their attention to finding out who had sent the disc.