UN High Commissioner for Human Rights urged Egypt on Tuesday to end its controversial “rotation” practice, which allows authorities to arbitrarily extend prison sentences beyond their maximum term.

Rotation is typically used against perceived political opponents, such as activists, protestors, lawyers, and journalists, and involves charging a prisoner with a new offense when they are about to be released, extending their prison term indefinitely. Often, new charges are for extremely similar, if not identical, offenses under the vaguely defined Anti-Terrorism Law.

The UN has previously decried this practice and Egypt’s anti-terrorism laws, specifically noting how rotation violates the “double jeopardy” rule, which states that someone cannot be punished more than once for the same offense.

Commissioner Volker Türk added that the majority of those affected by the practice should never have been arrested in the first place, noting that “the charges brought against them are often related to the exercise of their legitimate rights to freedom of expression and peaceful assembly …This practice has become a tool by which the Egyptian Government represses those perceived to be critical of, or in opposition to, its policies.”

Lawyer and human rights defender Ebrahim Abdelmonem Metwally has been subjected to prolonged arbitrary detention under the rotation system since 2017, when he was arrested in Cairo on his way to Geneva for a meeting with the UN Working Group on Enforced or Involuntary Disappearances. Although he has been ordered to be released twice, each time he has been charged with additional crimes under the Anti-Terrorism Act, thus extending his detention. He is currently being held in solitary confinement in Tora prison. Over 20 NGOS and the UN have demanded his release, and countless others remain in similar situations.