The Basque separatist group ETA, in a statement published Thursday by Basque-language newspaper Gara, announced it was formally ending its 50-year campaign of violence.
"We have a historic opportunity to find a just and democratic solution for the centuries' old political conflict," the statement read.
The group said it was influenced by a conference Monday in San Sebastian in which Sinn Fein nationalist leader Gerry Adams of Northern Ireland and former U.N. Secretary-General Kofi Annan appealed for peace.
European Commission President Jose Manuel Barroso, in a statement, called the cease-fire a historic moment for the Spanish people.
ETA, listed as a terrorist organization by Spain, France, the European Union and the United States, has demanded a separate Basque state in northern Spain and southwestern France. The group is blamed for more than 820 deaths in its fight for independence.
Tommy Vietor, a spokesman for the U.S. National Security Council, said the Spanish government was recognized for its courage in enduring years of violence.
"Yesterday's announcement by ETA in Spain that it has renounced violence holds out the prospect of a historic step toward peace, although there is a long road ahead to realize this promise," he said.