Basque civil society groups and international observers say an event next month in southern France will be key to ending the Basque conflict.

Organizers had said that "important elements for the process of demobilization" of ETA would be announced Monday, but they refrained from mentioning the separatist militant group at their news conference in Bayonne.

Observer Raymond Kendall, former Interpol general secretary, says the May 4 meeting in Cambo-les-Bains will aim "to lay a new stone on the path of a just and lasting peace."

Basque media reported last week that ETA would announce that it was disbanding the first weekend in May.

ETA killed more than 800 people in Spain and France as part of its struggle for an independent Basque country before ceasing its armed campaign in 2011.