Vice President Joe Biden didn’t mince words when asked on PBS NewsHour about a complaint President-elect Donald Trump posted to Twitter about how the Obama administration was handling the transition.

Biden said it was now time for Trump to “be an adult.” He added: “You’re president. You’ve got to do something. Show us what you have.”

Trump recently criticized “President O” for his recent critical statements, tweeting “Doing my best to disregard the many inflammatory President O statements and roadblocks. Thought it was going to be a smooth transition – NOT!”

He also called Senate Minority Leader Chuck Schumer “the head clown.” It was those tweets that prompted the put-down from Biden.

“Grow up, Donald. Grow up. Time to be an adult,” he said. “You’re president. You’ve got to do something. Show us what you have. You’re going to propose legislation. We’re going to get to debate it. Let the public decide. Let them vote in Congress. Let’s see what happens.”

He added: “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 also raised concerns about Trump skipping U.S. intelligence briefings as if they weren’t necessary.

“I think it’s dangerous,” he said in the interview. “For a President not to have confidence in, not to be prepared to listen to the myriad of intelligence agencies from defense intelligence, to the CIA, et cetera, is absolutely mindless. It’s just mindless.”