"Mr. President are you worried about indictments coming down in this investigation?" Acosta asked, as he pressed Trump on the migrant caravan.
Trump responded: "CNN should be ashamed of itself having you working for them. You are a rude terrible person you shouldn't be working for CNN. Go ahead. You're a very rude person the way you treat Sarah Huckabee is horrible and the way you treat other people are horrible. You shouldn't treat people that way. Go ahead. Go ahead Peter."
CNN responded in a tweet, defending Acosta and saying, "This President's ongoing attacks on the free press have gone too far. They are not only dangerous, the are disturbingly un-American. While President Trump has made it clear he does not respect a free press, he has a sworn obligation to protect it. ..."
The president's mood turned sour Wednesday after reporters pressed him on why he referred to a migrant caravan making its way to the U.S. on foot through Mexico as an "invasion." Trump ramped up his anti-immigrant rhetoric against the caravan in the final days of the midterm elections.
Trump was also pressed on why his campaign aired an ad featuring a Mexican immigrant convicted of killing American police officers and linking the man's actions to the caravan.
Several television networks pulled the ad after airing it or declined to air it at all.