Trump has had a long-standing feud with CNN and often tweets negatively about the network's coverage of him. "Of course, it happens to be NBC, which is possibly worse than CNN", Trump groused.
"The president called out one of my colleagues, Kristen Welker of NBC News, as dishonest, he said NBC News was dishonest", he said. "For the President to call her dishonest is unfair".
Trump then chose to call on a reporter from what he described as a "real network" - Fox News White House reporter John Roberts.
During his opening remarks, President Trump stressed that the relationship with the United Kingdom is better than ever and backed Prime Minister May's handling of Brexit.
"I do not take questions from CNN", Trump said.
Trump looked back over his shoulder and gave Acosta the shortest sound bite in presidential history. "It's called fake news and we solve a lot of problems with the good old recording instrument". I don't take questions from fake news. "Let's go to a real network".
Roberts had issued a statement defending Welker and his decision to ask a question after being called on by Trump in response to backlash for not supporting Acosta.
In the statement, Roberts said he had proceeded with his question when "it became clear that the president wasn't going to entertain a question from [Acosta]".
But Roberts, who used to work at CNN, defended the network in his statement.
'Given that the president took a question from a CNN reporter in his North Atlantic Treaty Organisation news conference just a day earlier, maybe he was letting off steam today rather than expressing an official stance toward a news organization's ability to report, but saying a news organization isn't real doesn't change the facts and won't stop us from doing our jobs, ' she said.