One-time US presidential contender Bernie Sanders spoke in favor of unionization at a largely African-American Mississippi Nissan plant, in an appearance that doubled as Democratic outreach in the wake of Donald Trump's election.

Sanders, who was bested by Hillary Clinton during the Democratic Party's primary, was accompanied by actor Danny Glover and other officials from the NAACP, which is the largest African-American advocacy group in the United States.

Organizers demanded that the company halt what they said was "ongoing harassment of African-American workers who are organizing to form a union."

They allege the factory's management threatened to illegally shut down the facility and terminate employment if workers unionized, and unlawfully interrogated workers.

The United Auto Workers labor union filed a complaint in May with the National Labor Relations Board claiming that Nissan was using deterrence tactics against workers who showed signs of unionizing.

Approximately 3,000 people turned out for the Canton, Mississippi march according to organizers.

"I am proud to join in fighting to give workers at Nissan's Canton, Mississippi, plant the justice, dignity and the right to join a union that they deserve," Sanders told the crowd.

The Vermont senator pointed out that unions were present in 42 of the 45 Nissan plants around the world.

"The American South should not be treated differently. What the workers at the Nissan plant in Mississippi are doing is a courageous and enormously important effort to improve their lives," he said.

Many manufacturers, particularly automakers, have set up plants in the US south where unions are not as ingrained in the social fabric.

Sanders, a leftist, self-declared socialist, made his debut in Democratic party leadership last November as chair of outreach, a sign that the bruised party has learned from the defeat of Clinton, who was an establishment candidate.

Her Republican counterpart, President Donald Trump, won office with tough talk and a populist economic message that was crucial to his victory.

The Canton, Mississippi plant, which opened in 2003, employs 6,000 people.

Source: AFP