Demonstrators rally for Trayvon Martin

Thousands of demonstrators march through Sanford, Florida - demanding the arrest of the neighbourhood watch volunteer who shot and killed an unarmed black teen a month ago.

They chant "no justice, no peace" as they walk through the town where 17-year-old Trayvon Martin was killed on February 26.

Protesters are calling for the arrest of 28-year-old George Zimmerman, who admitted he killed the teen with a semiautomatic handgun.

Zimmerman said he fired his gun in self defence during a fight with Martin, and his family said reports that Zimmerman was the aggressor are misleading and false.

Local police have declined to arrest the white Hispanic man, citing Florida's "Stand Your Ground" law, which allows violence in self defence.

But critics of the law say it gives individuals too much latitude to use deadly force when a threat is perceived.

The ensuing public outcry has prompted ongoing state and federal investigations and charges of racial bias.

The Reverend Al Sharpton spoke to demonstrators in the Orlando suburb.

(SOUNDBITE) (English) REVEREND AL SHARPTON SAYING:

"We are living in the middle of an American paradox. We've made great progress and at the same time in some areas we haven't moved at all. American paradox that we can put a black man in the White House but we can't walk a black child through a gated area in Sanford, Florida."

The demonstration was one of the largest held in Sanford.

Organizers of the rally said they were committed to non-violence, and noted there had been no arrests or disturbances.

Travis Brecher, Reuters