Several thousand people have marched in the northern city of Bilbao to express support for members of the Basque separatist group ETA who are currently serving jail terms for terror crimes.

Protesters chanted slogans on Saturday calling for ETA prisoners to be brought back to serve their sentences in prisons within the Basque region.

Spain has for decades dispersed such prisoners to jails across the country to make it difficult for them to communicate among themselves.

ETA is considered a terrorist organization by Spain, the U.S. and the European Union.

It is blamed for the killings of more than 825 people in a campaign of bombings and shootings aimed at achieving an independent Basque state straddling Spain's border with France.

The group has been decimated by arrests in recent years.