Vice President Joe Biden during an interview with PBS on Thursday. PBS Joe Biden had a strong message Thursday for President-elect Donald Trump two weeks away from Trump's inauguration: Grow up.

The vice president made the critical remarks during an interview with PBS on Thursday. Asked to comment on Trump's frequent use of Twitter, particularly a recent tweet in which he called Senate Minority Leader Chuck Schumer the "head clown" of the Democratic Party, Biden didn't pull any punches.

"Grow up, Donald," Biden said. "Grow up. Time to be an adult. You're president. You gotta do something. Show us what you have."

Biden then warned Trump about how the president-elect's job would change after the January 20 inauguration.

"You're going to propose legislation," Biden said. "We're going to get to debate it. Let the public debate it, let them vote in Congress, let's see what happens. It's going to be much clearer what he's for and against and what we're for and against, now that it's going to get down to actually discussing in detail these issues that affect people's lives."

Biden's political plans after he leaves office are unclear — he has alternately floated the idea of a presidential run in 2020 and tamped down expectations for a return to politics.

Watch the exchange below: