(CNN) -- Thousands gathered in Spain's capital Saturday to protest violence in Western Sahara, a long-disputed region of northwestern Africa, CNN's Spanish affiliate reported.
Deadly clashes erupted earlier this week between Moroccan forces and local rebels in the contested region.
The violence coincided with a round of talks -- informally backed by the United Nations -- between Morocco and representatives of Polisario Front, the region's independence movement.
Polisario said Moroccan authorities raided a camp on Monday in Western Sahara, leaving 19 people dead, 723 wounded and 159 missing. Morocco's official news agency said eight Moroccan police officers died in the raid.
Protesters on the streets of Madrid chanted and carried banners, demanding Morocco quit the territory that it annexed in the mid-1970s after Spain gave up control.
Actor Javier Bardem was among the protesters, the affiliate reported.
"Morocco guilty, Spain responsible," demonstrators shouted, CNN Plus reported.
The third round of the U.N.-backed talks ended this week, with both sides agreeing to continue discussions in December and early next year.
The meetings took place in the New York City area at the invitation of Christopher Ross, the U.N. secretary-general's personal envoy for Western Sahara.
A communique issued at the end of talks Tuesday night said there were "broad and frank" discussions of each side's proposals, but "each party continues to reject the proposal of the other as a basis for future negotiations," the United Nations said Wednesday.
The communique cited confidence-building measures, such as flights aimed at connecting Sahrawi refugees living in camps in Algeria's Tindouf region with their relatives in Western Sahara.
The neighboring countries of Algeria and Mauritania are also involved in the discussions about the territory.