President Trump had a contentious exchange with Washington Post journalist Philip Rucker at Thursday's coronavirus task force briefing. 

Following the task force's presentation about the virus's vulnerability to sunlight and humidity, Rucker asked the president if it's "dangerous" for him to suggest that it's safe for people to go outside, pointing to the death counts in places with warmer climates like Florida and Singapore. 

"Here we go, here we go -- the new headline is 'Trump asks people to go outside -- that's dangerous,'" Trump mocked Rucker. "You ready? I hope people enjoy the sun and if it has an impact, that's great."

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Trump highlighted the prior "rumor" that heat is effective in killing the virus and questioned if "light and heat" can be applied to a cure, stressing that he's "not a doctor" but that it may or may not work. Dr. Deborah Birx said having a fever helps the body respond to the virus, though expressed uncertainty about Trump's suggestion.

However, none of that sat well with the Post's White House bureau chief, who is also an MSNBC analyst. 

"But respectfully, sir, you're the president and people tuning in to these briefings -- they want to get information and guidance and want to know what to do. They're not looking for a rumor," Rucker said.

"Hey Phil, I'm the president and you're fake news," Trump shot back. "And you know what I'll say to you? I'll say it very nicely. I know you well, I know you well because I know the guy, I've seen what he writes. He's a total faker. So, are you ready?... It's just a suggestion from a brilliant lab by a very, very smart man. He's talking about sun, he's talking about heat. And you see the numbers. So that's it. That's all I have. I'm just here to present talent. I'm here to present ideas because we want ideas to get rid of this thing."

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After his praise for Bill Bryan, the head of the science and technology directorate at the Department of Homeland, Trump added, "And if heat is good and if sunlight is good, that's a great thing as far as I'm concerned."