The declaration also appeared to fall short of guaranteeing that the armed struggle would never resume.

The ETA video showed the statement being read in Spanish by one of three ETA activists seated at a table flanked by Basque nationalist banners, wearing black berets and capes, and white masks. Intermediaries with recent access to ETA leaders identified the three as members of the group’s General Command.

The commanders emphatically reasserted the goal of independence, and at the end of the video joined in traditional ETA rallying cries delivered with clenched-fist salutes. “The fight for independence for the Basque homeland goes on!” they cried.

Another concern centered on the fact that the announcement was made in what amounted to a political void. Mr. Zapatero’s Socialist government and the center-right Popular Party, a strong favorite to win a general election on Nov. 20, appeared to have played no part in the negotiations leading to the announcement. The Popular Party has strongly opposed any quick peace deal, insisting that ETA not only renounce its violence and disarm, but also dissolve on terms to be negotiated with the authorities in Madrid.

Instead, the declaration followed an appeal to ETA by a group of informal peace negotiators who met this week in San Sebastián, the political center of the main Basque homeland in Spain. The group included Kofi Annan, the former secretary general of the United Nations; Gro Harlem Brundtland, a former Norwegian prime minister; and Gerry Adams, the leader of the Irish nationalist group Sinn Fein, which has long had ties to ETA and has itself managed a metamorphosis from armed to political struggle.

The group issued a communiqué on Monday, saying it was “time to end, and possible to end, the last armed confrontation in Europe.”

Although home to fewer than 3 million of Spain’s 46 million people, the Basque region has a disproportionate economic importance as a center of industry, mining and culture. Bilbao, one of Spain’s largest cities, with close to a million people, has a Basque majority, and is home to the Guggenheim Museum Bilbao, one of Europe’s most celebrated centers for modern art. San Sebastián is world renowned for its cutting-edge cuisine.