Michaella McCollum and Melissa Reid have been told that prosecutors in Peru will not accept their guilty pleas on drug charges.
The pair will need to appear in court again to provide more information on the drugs gang that sent them to Peru to collect 11 kilograms of cocaine and explain their earlier claim that they had been forced to smuggle the drugs at gunpoint.
By pleading guilty yesterday the pair had hoped to have the maximum eight year sentence reduced to six years and eight months when they were sentenced next Tuesday.
Prosecutor Juan Rosas said that he will now ask for a new hearing to give Michaella McCollum, from Dungannon, Co Tyrone and Melissa Reid of Glasgow the chance to offer a more complete confession.
The two were arrested on August 6th in a Peruvian airport after attempting to sneak €1.7 worth of cocaine out of the country. They have spent the past month in a prison capital city Lima.