(CNN) President Donald Trump says he's offered a grim assessment of the worsening novel coronavirus outbreak to his 13-year-old son.

"I've spoken actually with my son, he says, 'How bad is this?'" Trump said during a coronavirus news conference on Monday, describing his conversations about the crisis with his youngest son, Barron.

"It's bad, it's bad," Trump added. "But we're going to be hopefully, a best case (scenario), not a worst case, and that's what we're working for."

That outlook is markedly different in tone from what Trump has offered previously on the outbreak, which he's attempted to minimize. Assuming a more solemn demeanor than at previous press conferences, Trump acknowledged that the coronavirus is not under control in the US or internationally. Just one day before, he's said that the virus is " something we have tremendous control of ."

He also unveiled new guidelines advising people to avoid gathering in groups of more than 10, going to bars, restaurants and food courts, and stop non-essential travel to staunch the spread of the pandemic.

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