Nearly 1,000 people staged a sit-down protest Monday morning in front of the immigration office in Baltic Sea port city of Rostock to protest the asylum policies of the world's major industrialized countries.
The rally started peacefully, but turned violent when some protestors began throwing bottles at police officers, said a police spokesperson. A photo journalist was injured.
Between 200 and 300 of the demonstrators Monday were radicals, many of them in black clothing and masks, a uniform which identifies them among friends and hides their faces from their police foes. Four demonstrators were detained there for violating a police ban on wearing masks at rallies.
As a sign of tribute, the demonstrators passed by a home for refugees in the Rostock-Lichtenhagen where neo-Nazis had terrorized Vietnamese asylum-seekers in 1992.
In an event that horrified many, the so-called "Sunflower House" was set on fire as neighbors stood watching.
On Monday, Protestors appealed for global freedom of migration and a loosening of asylum and immigration laws in industrialized countries to open doors to migrants from developing countries. Part of the anti-G8 movement regards immigration laws as racist and oppressive because rules prevent poor people from moving to Germany to live.
Monday's incident was the second outbreak of violence in Rostock in the run-up to the Group of Eight summit, which begins Wednesday in nearby Heiligendamm.
At demonstrations on Saturday, nearly 1,000 people were injured, including 433 police officers.