Spanish riot police used force late Thursday to disperse hundreds of demonstrators who gathered at the interior ministry to protest the closure of Madrid's main square.

The Spanish daily newspaper El Pais showed images of protesters, some of them with blood on their faces, being surrounded by police or dragged in handcuffs. El Pais said three people were arrested and nine were injured, two of them with head injuries.

Protesters blocked traffic in central streets after trying unsuccessfully to regain Madrid's Puerta del Sol square, which has been the scene of protests against Spain's economic austerity measures, high unemployment and political leadership since mid-May.

The movement has spread to other Spanish cities and to Greece.

Since Tuesday, police have prevented protesters from entering the square. Demonstrators marched several kilometers across the city Thursday evening to protest the action. Police say they were forced to intervene after some protesters tried to climb the ministry's fence.

Demonstrators say there was no provocation.

Spain's unemployment rate of about 21 percent is among 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.