Cannes, France - Actor Robert De Niro told AFP Wednesday that many in Hollywood share his views on President Donald Trump – whom he denounced at the Cannes film festival opening – but the industry is worried about speaking out against him.

The 81-year-old, one of the most outspoken critics of the American leader, used his Tuesday evening speech to condemn him again, calling him a "philistine".

"They have big businesses, they have to worry about the wrath of Trump, and that's where they have to make a decision: do I succumb to that or do I say no?" he told AFP.

But he cited as an inspiration the example of some colleges and legal firms who have stood up to attempts from Trump's administration to cow them.

Miley Cyrus Miley Cyrus finally addresses family feud rumors in rare public statement

"It's important, because other people pick that up, they see that they're fighting, it gives them strength to fight, and they're inspired by that," he added.

"They say it is possible... that's what America is about."

After accepting an honorary Palme d'Or on Tuesday evening for his contribution to cinema, the Taxi Driver star called for resistance against Trump's agenda.

As well as calling the president a "philistine", De Niro slammed his desire to implement 100% tariffs on films "produced in foreign lands".

"You can't have apathy, you can't have silence," De Niro said on Wednesday.

"People have to speak up, and they have to take chances and risk being harassed. You just can't let the bully win, period."