The verbal attack came following what Trump described as Trudeau's "false statements" on trade relations during the closing G7 news conference.
"Mr. De Niro's comments were unscripted and unexpected".
Senators Move To Reverse Trump's Deal Lifting Sanctions On China's ZTE
Senator Marco Rubio (R-FL) told the Wall Street Journal that he agrees the penalties are severe. "For me, it was more than that". The move came amid lawmakers' escalating objections on national security grounds to Trump's softening on ZTE since last month.
In two tweets that announced the end of US support for the joint G-7 statement, Trump claimed Trudeau made "false statements" during a prior news conference and went on to lambaste the Canadian leader. Trump called Trudeau "dishonest" and "weak" following the summit on Saturday. Trump advisers also ripped Trudeau, branding him a back-stabber.
He suggested the comments were insensitive to the fact that Trump was trying to look strong on his way to an important summit with North Korea and said there is a "special place in hell" for people like Trudeau.
This isn't the first time De Niro has gone after Trump.
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United are believed to be paying over £50m to secure the signature of the player, who was linked with City in the January transfer window.
De Niro's negative opinions about Trump are nothing new. During the opening lunch at the Tribeca Film Festival in April, the actor called Trump a "mad man" and a "low life".
"Bruce, you can rock the house like nobody else", said De Niro.
The CBS television network, which was broadcasting the event live but with a delay of a few seconds, scrambled to bleep out De Niro's expletive.
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No one has been killed by this period of activity, but one man was seriously injured when a lava bomb hit him in the leg. He said: "We can't fix everything". "There is no magic wand for this event", said Robert Fenton, a FEMA administrator.