Thousands of protesters who are camped out in Madrid's central Puerta del Sol square and in dozens more Spanish cities have pledged to defy an order to pack up their tent cities and leave.
As the country's electoral authorities ordered them to move by midnight on Friday, claiming they would disturb Sunday's municipal and regional elections, organisers called a special silent protest for first thing on Saturday morning.
A tense standoff between police and protesters looked inevitable as interior minister Alfredo Pérez Rubalcaba warned that authorities would uphold the law.
"Police know exactly what they have to do," he said, without specifying. "Their actions will depend on what happens."
"We are expecting some kind of attempt to get rid of us," warned organisers in southern Seville, where several hundred people were also camped out in a city square.
But protesters claimed their "silent" demonstration in Madrid on Saturday would not break rules preventing campaigning on the day before an election.
More than 10,000 people had gathered in the small hours of Friday morning in support of the campers who first appeared in the Puerta del Sol square on Sunday.