Robert De Niro has been denied a prestigious award after making a speech calling Donald Trump a "clown" and a "dictator "outside the former president's trial.

The actor, 80, joined a Democrat-organised event on Tuesday outside the New York court where Trump was on trial for falsifying business records to cover up an affair before the 2016 presidential election.

Standing by Manhattan Criminal Court, De Niro tore into the Republican - calling him a "monster" - and argued with Trump supporters who he called "gangsters".

The National Association of Broadcasters (NAB) decided to rescind an offer to award De Niro with the Leadership Foundation's Service to America Award, which he was set to receive on Tuesday.

A spokesperson said the event at which the actor would have received the prize "is proudly bipartisan, uniting those from across the political spectrum to celebrate the impactful work of local broadcasters and our partners".

They added: "While we strongly support the right of every American to exercise free speech and participate in civic engagement, it is clear that Mr De Niro's recent high-profile activities will create a distraction from the philanthropic work that we were hoping to recognize.

"To maintain the focus on service of the award winners, Mr. De Niro will no longer be attending the event."