Since Sunday, they have taken down several of the wooden structures covered in blue plastic tarpaulins so as to “use less space” in the central Puerto del Sol square, said Paco Andres, a spokesman for the organisers.

Growing numbers of homeless people are also taking advantage of the encampment to pitch their own tents in the square.

Spain’s protests over the economic crisis began May 15 and fanned out to city squares nationwide as word spread by Twitter and Facebook among demonstrators known variously as “the indignant”, “M-15”, “Spanish Revolution” and “Real Democracy Now.”

During the night of Monday to Tuesday, only several dozen demonstrators remained in the Puerta del Sol, three weeks after several thousand had gathered there ahead of May 22 local elections.

Now the movement, a rallying point for millions of Spaniards furious over unemployment that has soared to 21.29 percent, is seeking ways to keep up the momentum.

Organisers plan several protests on a national scale, including one on June 11, the day when local mayors elected on May 22 are sworn into office, and another on June 19.

Most of the demonstrators in the Madrid camp do not hide their desire to leave as soon as possible.

But the decision must be taken by a general assembly of all those present, a vote that has been repeatedly delayed due to heavy rain.

The site is now also occupied by many homeless people, creating increasing security problems.

“There are a lot of people here who are drinking, who fight, who have nothing to do with the movement,” said one 19-year-old protester who gave his name only as Rodrigo.

He pointed to a rather agitated group around some tents in the middle of the camp.

“We must take more action, we should have taken down the camp earlier,” he said.

In Barcelona, demonstrators on Tuesday debated whether to maintain their tent village in the central Plaza de Catalunya.

Anti-riot police fired rubber bullets and swung truncheons on May 27 to disperse protesters in the Plaza Catalunya ahead of celebrations of Barcelona’s Champions League victory.

A total of 87 people including one police officer were treated, mostly for light injuries.

By that same evening, however, at least 5,000 people were back in the square and some had put tents back up.