International mediators are holding a peace gathering to mark the end of Basque separatist group ETA after a decades-long campaign against Spain that saw more than 850 people killed.

Basque civilians are also taking part in Friday's conference in the southern French town of Cambo-les-Bains — but the Spanish and French governments are not.

In an open letter Thursday to the Basque people, ETA said it has "completely dismantled all of its structures" and "will no longer express political positions, promote initiatives or interact with other stakeholders."

Victims' groups dismissed the move as propaganda, and the Spanish government said it would continue to prosecute anyone with any links to past violence.

ETA staged bombings, shootings and kidnappings as it sought to create a new Basque homeland in northern Spain and southern France.