The announcement will be made at a press conference next Monday where mediators in the talks between ETA and Spanish authorities will outline the details, the NTN24 television channel said.
The armed leftist group, called Homeland and Liberty in the Basque language, was created in 1959 in a bid to win independence for the Basque Country. It has killed over 800 people, receiving a terrorist designation in Spain and several other countries.
In April previous year, the group announced that they intended to disarm. French Interior Minister Matthias Fekl then welcomed the move by the group, which provided the French authorities with a list of arms cashes as part of its disarmament program.