While the Socialists currently lead, polls show they and anti-austerity party Podemos would not win enough seats between them to govern, leaving open the question whether the centre-right Ciudadanos party would align with them or join a grouping of the conservative People’s Party (PP) and the far-right Vox party.
Sanchez has been savaged by the PP, centre-right Ciudadanos and more recently the small far-right party Vox.
“Mr Sanchez, that’s enough, it’s over ... call elections now!” said the head of the centre-right Ciudadanos Albert Rivera.
The centre-right party Ciudadanos has called another rally next Sunday in Barcelona “in defence of the Constitution”.
Recent opinion polls have shown the conservative Popular Party, centre-right Ciudadanos and far-right Vox could together win a majority of seats in parliament if elections were held, allowing them to replace the Socialist government.
The centre-right People’s Party, Ciudadanos and far-right Vox have called for thousands to take to the streets of Madrid on Sunday draped in Spanish flags to protest against what they called a treasonous deal being prepared by the government.