Spain's Justice Minister Alberto Ruiz-Gallardon, left and Interior Minister Jorge Fernandez Diaz prepare to start a joint news conference at the Justice Ministry in Madrid, Spain, Monday Oct. 21, 2013 (Photo: AP)
Europe's human rights court Monday ordered Spain to free an ETA prisoner and opened the door to the release of scores of other armed Basque militants and common criminals.
The European Court of Human Rights upheld a previous ruling in favour of releasing Ines del Rio Prada, a 55-year-old jailed member of the armed Basque separatist group.
The decision could open the jail doors for scores of other prisoners in the same situation as Del Rio Prada, who has been behind bars since 1987 after being sentenced to 3,838 years for terrorist-related offences including 19 killings.
Spain lamented the ruling by the Strasbourg-based court.
"I regret this decision," Justice Minister Alberto Ruiz-Gallardon told a news conference in Madrid, adding however that it would be up to the Spanish courts to decide how the verdict applied to other cases.
The European court, upholding a decision first handed down in July 2012, said Spain should "ensure that the applicant was released at the earliest possible date".
It also told Spain to pay her 30,000 euros ($41,000) in damages and 1,500 euros for costs and expenses.
The court condemned Spain for retroactively applying a legal practice known as the "Parot doctrine" to extend the time convicts spend in prison.
The doctrine, adopted by the Spanish Supreme Court in 2006, said that years of remission earned through prison work should be deducted from the total sentence -- often amounting to hundreds of years -- instead of the 30-year limit on prison terms.
In Del Rio Prada's case, the new doctrine wiped out her remission and extended her prison time by nearly nine years.
One of her lawyers, Didier Rouget, welcomed the verdict.
"It is a decision that shows that the Spanish state violated human rights and notably the rights of the prisoners in an extremely serious manner," he said.
The Geneva-based International Commission of Jurists said the "highly significant" judgement meant courts could not retroactively apply rules that increase prisoners' sentences.
The same doctrine was used retroactively to lengthen the prison terms of 54 ETA prisoners, nine prisoners from other armed groups that have since been broken up, and 14 common criminals, according to Spain's Interior Ministry.
It was first applied in February 2006 to ETA prisoner Henri Parot.
ETA, listed as a terrorist group in the United States and Europe, is blamed for the deaths of 829 people in a four-decade campaign of shootings and bombings for an independent homeland in northern Spain and southern France.
Victims of ETA's violence urged Spain to refuse to bow to the Strasbourg court's ruling.
"First, we are going to ask that we don't comply. And of course there is no reason to open the jail doors because they will have to lodge an appeal one by one," said Angeles Pedraza, head of the Association of Victims of Terrorism (AVT).
"This is not justice. Despite being defeated today, the AVT and the victims will fight to the last for justice in Spain. And justice means the terrorists are in jail and the victims can mourn," she told reporters in Madrid, surrounded by victims of ETA's violence.
In October 2011, ETA declared a "definitive end to armed activity" but it has not formally disarmed nor disbanded as the Spanish and French governments demand.
Interior Minister Jorge Fernandez Diaz stressed that the government would not change its policy of refusing to negotiate with ETA.
ETA has been severely weakened in recent years by the arrests of its senior leaders in Spain and France.