Supporters of Spanish conservative and centrist parties have held a protest in Madrid against government plans to hold talks with Catalan separatists.
The centre-right Popular Party (PP) and Ciudadanos (Citizens) say Prime Minister Pedro Sánchez's plan to appoint an intermediary for the talks amounts to treason.
The separatists have rejected the offer - they want a new independence vote.
Like the right, the ruling Socialists also oppose Catalan independence.
Far-right groups including the Vox party are also present at the protest, held under the slogan "For a united Spain. Elections now!"
Protesters filled the Spanish capital's Colon Square and nearby streets, many of them chanting "long live Spain". Police put the total number of demonstrators at 45,000.
What are the protesters saying?
They say the government's offer to separatists to hold round table talks and appoint a special rapporteur amounts to a capitulation and they want elections scheduled for 2020 brought forward.
One protester, Mabel Campuzano, told Reuters news agency that Mr Sánchez was "betraying Spain and we think that Spaniards don't deserve him as the president of the government".
In a speech, PP leader Pablo Casado denounced Mr Sánchez's policies as "Socialist surrender" and "deals under the table", Efe news agency reports.
"Sánchez's time is over," Mr Casado said, adding that the protests were a turning point and the beginning of a return to "harmony and legality" in Spain.