Former US president Donald Trump announced Wednesday he is filing a class-action lawsuit against Facebook, Twitter and Google, escalating his years-long free speech battle with tech giants who he argues have wrongfully censored him.

"I'm filing, as the lead class representative, a major class-action lawsuit against the big tech giants including Facebook, Google and Twitter as well as their CEOs, Mark Zuckerberg, Sundar Pichai and Jack Dorsey -- three real nice guys," Trump told reporters at his golf club in Bedminster, New Jersey.

The nation's top tech firms have become the "enforcers of illegal, unconstitutional censorship," added the 75-year-old Republican, who was banned from posting on Facebook and Twitter in the wake of the deadly January 6 siege of the US Capitol by his supporters.

Trump says he is being joined in the suit by the America First Policy Institute and thousands of American citizens who have been "de-platformed" from social media sites.

"Through this lawsuit we are standing up for American democracy by standing up for free speech rights of every American -- Democrat, Republican, independent, whoever it may be," Trump said. "This lawsuit is just the beginning."

Trump said he is filing the suit in US District Court in southern Florida, where he is seeking an immediate halt to censorship, blacklisting and what he called the "cancelling" of people who share his political views.

Trump stressed that he is not looking for any sort of a settlement. "We're in a fight that we're going to win," he said.

Facebook banned Trump indefinitely on January 7 over his incendiary comments that preceded the Capitol insurrection by his supporters one day earlier.

Twitter quickly followed suit and permanently suspended Trump's account due to the "risk of further incitement of violence."

In June, following a review by Facebook's independent oversight board, Facebook narrowed the ban to two years.

Trump said YouTube and its parent organization Google have deleted "countless videos" addressing the handling of the coronavirus pandemic, including those that questioned the judgement of the World Health Organization.

The Republican billionaire, his allies and many supporters say the ban on Trump and others amount to censorship and abuse of their power.

"There is no better evidence that big tech is out of control than the fact that they banned the sitting president of the United States," Trump said.

Trump has begun a series of public engagements, including campaign-style rallies, as he seeks to maintain his status as the most influential Republican in the nation.

He has teased a potential 2024 presidential run but has made no announcement on his political future.