Hundreds of thousands of people demonstrated around Spain on Sunday against a planned amnesty for Catalan separatists.
Prime Minister Pedro Sanchez has promised amnesty to two Catalan pro-independence parties as part of negotiations to secure another four-year term in office.
Sanchez must form a government by November 27, otherwise snap elections will be held on January 14.
Opposition conservatives demand new election
Participants at a rally in Madrid carried signs reading "No to amnesty, yes to the constitution" and "Sanchez traitor."
The leader of the conservative People's Party (PP), Albert Nunez Feijoo, who took part in one of the demonstrations, said he expected protests to continue until a new election is called.
The PP took the most seats in Spain's parliament in elections in July, but failed to reach an absolute majority and does not have enough support to form a governing coalition even alongside the third largest group, the far-right Vox party.
The PP said that some 2 million people came to the rallies, including one million people in Madrid alone.
No official estimates for the protests had been given yet.
PSOE to offer amnesty to Catalan secessionists
Catalan secessionist parties pressed ahead with an independence referendum in 2017 although it had been ruled unconstitutional by the Supreme Court, after which many lawmakers and political figures were arrested and charged with rebellion.
The PSOE had ruled out offering separatists amnesty during its electoral campaign.
However, after the July 23 election it became clear it could only govern with the support of the pro-independence Junts and Republican Left of Catalonia parties. The leader of Junts, Carles Puigdemont, is currently living in exile in Belgium.
Sanchez says that he aims to defuse the Catalonia conflict through dialogue and compromise.
sdi/msh (dpa, AFP)