Tens of thousands of people demonstrated Saturday evening in the Spanish capital Madrid against the possible negotiations between the government and the Basque underground organization ETA, according to DPA. Protestors called on Prime Minister Jose Luis Rodriguez Zapatero to make no concessions in the fight against terrorism. The demonstration, marching under the motto "Not in My Name," was supported by the opposition People's Party (PP) and the Bishop's Conference. Among those participating were PP head Mariano Rajoy and former prime minister Jose Maria Aznar. The protest marked the third mass demonstration against the anti- terrorism policies of the socialist-led government in a year. Zapatero has declared readiness to negotiate with ETA should the group renounce violence. Speculation was widespread in Spain of an upcoming "ceasefire" with ETA, which the organization last week rejected in a statement.