Basque separatist group Eta has said it will not relinquish weapons until the region gets independence from Spain.
Eta announced a permanent ceasefire in March
Three hooded gunmen told an Eta rally in northern Spain their fight was not a thing of the past, despite a ceasefire announced six months ago.
Speaking after the statement, Spain's prime minister said he would work towards ending 40 years of violence.
His government has indicated that it is ready to talk to Eta, but has ruled out Basque independence.
The BBC's Danny Wood, in the Spanish capital Madrid, says this is the sixth communication by the armed separatist group since it declared a permanent ceasefire in March.
He says it could be the strongest sign yet that Eta is not prepared to give up the violent struggle for independence - or just a strategy before starting talks with the national government.
Saturday's rally was held in the town of Aritxulegi, near San Sebastian.
In their statement, reported by Basque media, the hooded gunmen said: "Until we achieve independence and socialism in the Basque country, we reaffirm our commitment to keep taking up arms firmly.
"The fight is not a thing of the past. It is the present and the future."
After the announcement, the militants fired shots into the air and disappeared into the forest.
In a speech in Barcelona, Prime Minister Jose Luis Rodriguez Zapatero said: "We are going to be firm as we go forward.
"The rules of the game are clear: respect for the law and peace, and peace means the absence of violence, of absolutely any kind of violence ... The end of violence has no price."
But the leader of Spain's conservative opposition, Mariano Rajoy, said the statement was a reminder that negotiating with terrorists was pointless.
"Eta has not changed - Eta is still a terrorist organisation," he said.