Tens of thousands of Basque separatist sympathizers marched in downtown Bilbao on Saturday calling for an amnesty that would allow ETA prisoners to serve out the remainder of their sentences in the northern Spanish region rather than in jails further afield.
Protesters marched to the city's town hall behind banners saying "Human rights, resolution, peace. Basque prisoners back home."
Some protesters waved Catalan flags in solidarity with another northern Spanish region with an important separatist movement. One large banner included a slogan in English, saying "Repatriate all Basque prisoners."
Spain has for more than two decades dispersed ETA prisoners under an amendment to the country's 1975 anti-terrorism law. One of the purposes of the law was to stop convicted Basque militants from communicating easily among themselves to plan subversive strategies.
"A large percentage of the Basque nation has been at this demonstration to ask the Spanish government to make a change," 58-year-old protester Maite Perez de Mendiola said.
There are an estimated 700 ETA prisoners held in jails dotted around Spain and France, and only around two dozen are believed to be in Basque region prisons.
ETA has killed 829 people since the late 1960s in bombings and shootings to force the creation of a Basque homeland in northern Spain and southwest France.
The organization pledged in October 2011 to stop using weapons in its bid for Basque independence, but it stopped short of saying it would disarm and allow inspections of decommissioned weapons, as happened with the IRA in Northern Ireland.
Inaki Olasolo, a spokesman for the protest, said the Spanish government could take advantage of "a historic opportunity to reach a solid peace with justice, with recognition and healing" if it allowed prisoners back.
Olasolo also called for the release of those suffering from terminal illnesses, of which it is believed there are three.
Although ETA — classified as a terrorist organization by Spain, the U.S. and the European Union — has declared two previous "permanent" cease-fires, many observers think this time they mean it. Waves of arrests in recent years have repeatedly weakened its structure and diminished its ability to carry out attacks or collect funds.
However, French police late Friday arrested two people who reportedly acknowledged being ETA members and one of the suspects was in possession of a firearm.
Associated Press writer Harold Heckle in Madrid contributed to this report.