President Trump lashed out at a reporter for CNN who challenged him on his immigration rhetoric during a news conference and refused to give up his microphone to allow other questions to proceed.

“That’s enough. That’s enough. That’s enough. That’s enough,” Trump told Jim Acosta, who covers the White House for the network, as a female aide tried to grab the microphone. “That’s enough. Put down the mic.”

“CNN should be ashamed of itself having you working for them,” Trump told Acosta. “You are a rude, terrible person. You shouldn’t be working for CNN. You’re a very rude person. … You shouldn’t treat people that way.”

The exchange took place during a White House news conference Wednesday related to the midterm elections.

Acosta had continued to speak and remained standing after Trump dismissed his questions about immigration and special counsel Robert S. Mueller III’s investigation of Russian meddling in the 2016 election.

Acosta challenged the president for calling a caravan of migrants in Mexico slowly making its way toward the U.S. border an “invasion.”

He also brought up a Trump campaign ad on immigration that major television networks refused to air because of content they considered offensive. The ad, which mentioned the caravan, depicted people climbing over walls.

“Do you think they were actors? They weren’t actors. They didn’t come from Hollywood,” Trump said, referring to the footage.

This is not Trump’s first such antagonistic encounter with Acosta. He has refused to take Acosta’s questions several times, and Acosta has become a focus of Trump supporters’ anger at rallies.

CNN released a statement after the exchange through one of its official Twitter accounts.

“The President’s ongoing attacks on the press have gone too far,” the statement read. :They are not only dangerous, they 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. A free press is vital to democracy, and we stand behind Jim Acosta and his fellow journalists everywhere.”