MADRID (AP) — Several thousand people have gathered in downtown Madrid to protest the release from jail of Basque separatists who were convicted of attacks but freed under a European Court of Human Rights ruling.

The Strasbourg-based court found that prisoners who had served time and completed sentence reduction programs couldn't have their jail terms re-interpreted by Spain's judiciary.

The court's decision centered on the case of Ines del Rio Prada who was sentenced in 1987 to a total of 3,828 years for multiple terror attacks carried out as a member of the armed Basque group ETA that killed 24 people.

Del Rio was due for release in 2008, but Spain's courts ruled her sentence reduction was applicable to her full sentence and not the 30-year maximum term the law allows.