A sea of people has marched on Washington for black lives justice on the anniversary of civil rights leader Martin Luther King Jr’s “I Have a Dream” speech.

Evoking the 1963 speech at the same location it was originally spoken, the Reverend Al Sharpton stirred the crowd, declaring: “You might have killed the dreamer, but you can’t kill the dream because truth crushed to earth shall rise again.”

“Get your knee off our neck. Enough is enough.”

Thousands of people at the “Commitment March: Get Your Knee Off Our Necks” protest. Photo: Getty

The 57th anniversary comes at the end of a summer of racial unrest and nationwide protests, sparked by the death of George Floyd, an unarmed African American, after a Minneapolis police officer kneeled on his neck for nearly nine minutes.

Earlier this week, protests seized Kenosha, Wisconsin, after police officers shot another African-American man, Jacob Blake, multiple times in front of his young children while his back was turned.

Blake survived the shooting, but has been paralysed, his lawyers told reporters earlier this week.

Friday’s protest, called “Commitment March: Get Your Knee Off Our Necks,” was planned in the wake of Floyd’s death by civil rights activist Reverend Al Sharpton’s National Action Network.

On the 57th anniversary of his father’s speech, Martin Luther King III urged people to vote in November, a common theme at the event.

“There is a knee upon the neck of democracy and our nation can only live so long without the oxygen of freedom,” he said.

“Our strength must be exercised by more than rhetoric and more than marching.”

He also noted the coronavirus pandemic had disproportionately affected minority communities in the US, stressed a message of “love and community” and encouraged activism.

“If you’re looking for a saviour, get up and find the mirror,” King said.

Poetry Pole of Baltimore, holds an African-American flag in the Lincoln Memorial Reflecting Pool. Photo: Getty

This summer’s uprisings drew parallels to those seen in 1968, after King’s own murder, five years after spoke the now-famous words.

King envisioned a time his children would “one day live in a nation where they will not be judged by the colour of their skin but by the content of their character.”

Washington requires people coming from so-called coronavirus high-risk states, which currently includes both Wisconsin and Minnesota, to quarantine for 14 days when visiting the district.

Organisers say they are taking the pandemic into account by restricting access to buses from those states, distributing masks and checking temperatures.

Black Americans take a stand for justice. Photo: Getty

-with AAP