Federal prosecutors in New York have added a conspiracy-to-commit-torture charge against former Venezuelan President Nicolás Maduro and his wife, Cilia Flores. The case concerns alleged abuse of Americans and others held by Venezuelan authorities.

In a superseding indictment, prosecutors allege that after taking office in 2013, Maduro authorized torture of specific people and oversaw a system of arbitrary detention and violence used to repress political opposition. The claims in the indictment have not been established in court.

The document describes alleged abuse of American and Venezuelan detainees, including beatings, electrocution, asphyxiation and rape. Prosecutors also allege that one detained American was forced to eat his own vomit. U.S. officials say more than a dozen American citizens were unlawfully held in Venezuelan prisons.

Federal prosecutor Jamie McDonald said after a hearing that Maduro, Flores and other senior officials used torture and repression to maintain power. CNN had reported on Wednesday that the charges were expected. A source familiar with the investigation told CNN that investigators had also discussed bringing charges against several other people.