Cairo, Feb 3 (IANS/RIA Novosti): More than 600 people were injured in clashes between police and protesters that broke out in downtown Cairo following a deadly football-match riot in Port Said, Egyptian authorities said Friday.

Thousands marched on Cairo's Tahrir Square Thursday to protest against what they called police negligence during Wednesday's football disaster that left more than 70 people dead and up to 300 injured.

Thursday clashes broke out when a group of several hundred protesters marched from the square to the nearby Interior Ministry headquarters, raising slogans against police and the country's military rulers.

Police used tear gas to disperse the protesters after they attempted to storm the ministry building, hurled stones at security officers and set fire to several cars and trees, the state television reported.

More than 200 of those injured in the clashes have been hospitalized, the Egyptian health ministry said in a statement. Earlier TV reports said some 10 police officers were among the injured.

The protests took place as Egypt announced a national three-day mourning period following the riot at the Port Said stadium. The riot had broken out Wednesday night when thousands of fans rushed onto the field after their home team from Port Said, Al-Masry, defeated Al-Ahly, one of Egypt's top clubs from Cairo, 3-1.