Thousands of people marched into Madrid's Puerta del Sol square Friday to protest police use of force on demonstrators who had rallied at the interior ministry a day earlier to protest the closure of the square.

The central plaza has become a symbolic site for “Los Indignados,” a movement that has been protesting Spain's high unemployment and the government's handling of the nation's economic crisis.

The rally took place one day after riot police clashed with protesters who had massed outside the interior ministry after trying unsuccessfully to gain access to the square for several days. At least 20 people were injured during Thursday's confrontation.

Spaniards angered about the economic situation have been staging regular protests in Madrid since May 15. The movement later spread to other parts of the country.

Spain's unemployment rate of about 21 percent is the highest in the 17-nation euro zone. The country also has one of Europe's highest public debts. Prime Minister Jose Luis Zapatero has tried to reduce the debt by cutting government spending, raising the retirement age and making it easier for companies to fire employees.

Many citizens blame inept politicians for the country's economic crisis.