The United Nations Working Group on Arbitrary Detention has asked Spain to seek the release from pre-trial jail of three Catalan separatists detained following Catalonia's 2017 secession attempt.
In an opinion to be published later Wednesday but seen by The Associated Press, the working group says that former Catalan regional vice president, Oriol Junqueras, lawmaker Jordi Sanchez and activist Jordi Cuixart were arbitrarily detained and their rights violated.
It also says that they should receive compensation for their time behind bars and that Spain should investigate their detentions.
The three are among a dozen separatist leaders on trial at Spain's Supreme Court on a number of charges, including rebellion.
Under Spanish law, suspects can be held in custody if they represent a flight risk, if the court believes they could commit possible further crimes, or if there is a risk they could destroy evidence.
Other leaders of the secession bid, including former Catalan regional president Carles Puigdemont, fled the country and are fugitives from Spain, while the current Catalan chief, Quim Torra, has promised to continue to push for independence.
The working group is made up of five independent, non-paid experts appointed by the Human Rights Council. The opinion matters for those countries mindful of international commitments.
The opinion's release comes one day after the European Court of Human Rights rejected a suit brought by Catalan separatist lawmakers claiming that Spain's top court violated their rights when it ruled to suspend a regional parliamentary session to declare independence two years ago.
In that decision, the European court said that Spain's Constitutional Court's decision had not violated their rights since its action was "aimed at protecting the Constitutional order" and taken "in the interests of public safety [and] for the prevention of disorder."
Junqueras and Puigdemont were both recently elected to the European Parliament, although they face legal hurdles to actually take their seats.