JENA La.

Thousands of chanting demonstrators filled the streets of this little Louisiana town Thursday in support of six black teenagers initially charged with attempted murder in the beating of a white classmate.

The crowd broke into chants of "Free the Jena Six" as the Rev. Al Sharpton arrived at the local courthouse with family members of the jailed teens.

Martin Luther King III, son of the slain civil rights leader, said the scene was reminiscent of earlier civil rights struggles. He said punishment of some sort may be in order for the six defendants, but "the justice system isn't applied the same to all crimes and all people."

The six teens were charged not long after the local prosecutor declined to charge three white high school students who hung nooses in a tree on their high school grounds. Five of the black teens were initially charged with attempted murder, but that charge was reduced to battery for all but one, who has yet to be arraigned; the sixth teen was charged as a juvenile.

"This is the most blatant example of disparity in the justice system that we've seen," the Rev. Al Sharpton told CBS's "The Early Show" before arriving in Jena. "You can't have two standards of justice."

"We didn't bring race in it," he said. "Those that hung the nooses brought the race into it."

Sharpton, who helped organized the rally, said this could be the beginning of the 21st century's civil rights movement, one that would challenge disparities in the justice system.

The district attorney who is prosecution the teens, Reed Walters, denied on Wednesday that racism was involved in the charges.

He said he didn't charge the white students accused of hanging the nooses because he could find no Louisiana law under which they could be charged. In the beating case, he said, four of the defendants were of adult age under Louisiana law and the only juvenile charged as an adult, Mychal Bell, had a prior criminal record.