Los Angeles community leaders issued a call for unity on the 20th anniversary of the city's deadly riots, one of the worst spasms of violence in modern US history.

But a small number of African American protestors used the anniversary to lash police at the epicenter of 1992 riots in deprived South LA, which left 53 people dead and caused more than $1 billion worth of damage.

The historic race-fueled mayhem was sparked by the acquittal ofpolice officers caught on video beating black motorist Rodney King, but were fueled by ethnic tensions and huge economic disparities in LA.

"We felt we were under attack," community activist Morris Griffin told a crowd Sunday at the junction of Florence and Normandie avenues, where some 150 mostly African Americans gathered for the "speakout" event.

A short time later another rally developed on the other side of the junction, with Los Angeles Police Department (LAPD) representatives as well as Latino, African American and Korean leaders vowing unity.

But the initial gathering, while dwindling to some 50-60 people, turned more negative, with protestors at one point shouting insults at the police as a female rapper spoke, an AFP correspondent reported from the scene.

"In my opinion they're not part of the solution because everything I hear from that side (of the street) is very negative and confrontational," said Michael Crosby, head of the local 77th Street Division LAPD Clergy Council.

"We already know what the problem is, so let's take some efforts to try to build a better community," he added.

Local radio and other media have hosted wall-to-wall debates about the lessons learned from the unrest, triggered by the acquittal of four police officers over the beating of King.

King -- who has released an autobiography timed with the anniversary -- was 26 years old when a group of white police officers brutally beat him while a bystander videotaped them from his apartment window on March 3, 1991.

A year later, on April 29, 1992, an all-white jury acquitted four police officers over his assault.

Hundreds of thousands of people poured into the streets in anger, igniting a wave of deadly violence and arson that swept through large areas of Los Angeles.

The run-up to the anniversary has seen a surge of reflection on what has changed in the decades since the riots, which were centered on South LA, primarily composed of African American and Hispanic communities.

On Sunday, LAPD assistant chief Michel Moore held a show of unity with leaders of the Korean American Coalition, the Anti-Defamation League, the LA Urban League and the Southern Christian Leadership Conference, among others.

"We recognize the tragedy of April 29, 1992 and honor those innocent victims who lost their lives," they said in a statement backed by others including the National Association for the Advancement of Colored People (NAACP).

"We pledge that our children will understand that diversity in our community is a strength and a source of pride, not a cause for hatred and division," said the joint statement.

King, who has battled drugs and had a number of brushes with the law since 1992, said racism still has to be challenged.

"There's always going to be some type of racism. But it's up to us as individuals in this country to look back and see all the accomplishments that we have gotten to this far."

"I have much respect for (the police), much respect... some of them went out of their way over the years to try to make it up to me. Not all of them are bad," he added.