Los Angeles: Donald Trump on Tuesday hit back at Robert De Niro, calling him a "very low IQ individual," after the Oscar-winning actor's expletive-laden attack on the American President on live television.

Two days after De Niro's outburst on the stage of the Tony Awards ceremony in New York, Trump said he had watched the clip "and (I) truly believe he may be punch drunk".

Representatives for De Niro did not immediately return a request for comment.

De Niro, one of the most respected American actors, twice used the so-called F-Bomb against Trump on Sunday, prompting loud applause from the audience of theatre actors, directors and producers at Radio City Music Hall. The Raging Bull actor's remarks were bleeped for more than 6 million Americans watching the awards show on CBS at home.

De Niro took the stage to introduce rocker Bruce Springsteen. Without any preamble, he said, "I'm gonna say one thing. F*** Trump."

Trump was on his way to Singapore to meet Kim Jong-un as the awards show was taking place. He delivered his response on his Twitter account while on his way back to the US. "Robert De Niro, a very Low IQ individual, has received to many shots to the head by real boxers in movies. I watched him last night and truly believe he may be 'punch-drunk',"? Trump tweeted. Reuters