BERLIN -- Nearly 1,000 people were injured in the riots that broke out Saturday during a demonstration against the June 6-8 Group of Eight (G8) summit, according to German police in the northern city of Rostock and protest organizers.

Police spokesman Frank Scheulen said that 433 police officers were injured, 30 of whom suffered serious injuries.

Around 520 demonstrators were wounded, primarily by stinging tear gas, and 20 of them were injured seriously, according to the protesters' spokeswoman Sabine Zimpel.

A march including organizations such as Greenpeace, anti-capitalist group Attac, Germany's Left Party, church groups and labor unions turned violent after demonstrators in black masks and hoods began to throw stones, bottles and flaming objects at police. The police responded with tear gas, water cannons and batons.

"We distance ourselves clearly from these violent people," Zimpel said.

Scheulen said most of the riot had ended by the evening, but two cars were set on fire during the night.

Police put the number of protestors at 25,000, while organizers said at least 80,000 went onto the streets of Rostock to protest against the G8 summit in Heiligendamm, 25 km from Rostock.

Leaders from the G8 industrialized nations of Germany, France, Britain, Italy, Japan, the United States, Canada and Russia, will attend the summit.

Germany will deploy about 16,000 police officers from all over the country to prevent unrest before and during the three-day summit.