WASHINGTON -- U.S. Sen. Cory Booker said lawmakers of both parties are "very worried" about President Donald Trump's performance in office.

Speaking on NBC's "Late Night" Monday evening, Booker supported Republican U.S. Sen. Bob Corker's recent tweet about the White House becoming "an adult day care center" and his comments to the New York Times about Trump putting the country "on the path to World War III."

"This isn't new," said Booker, D-N.J. "This is one of the worst-kept secrets in Washington that Republicans and Democrats are very worried about the person who's sitting in the White House."

Booker sits on the Senate Foreign Relations Committee that is chaired by Corker, R-Tenn. Corker backed Trump for president, unlike some of his Senate Republican colleagues, and had been a loyal supporter of the president's agenda.

Trump responded to Corker's comments via Twitter on Tuesday.

The Failing @nytimes set Liddle' Bob Corker up by recording his conversation. Was made to sound a fool, and that's what I am dealing with! — Donald J. Trump (@realDonaldTrump) October 10, 2017

Booker also described Defense Secretary Jim Mathis as a "bulwark" standing "between Donald Trump and disaster," and said the U.S. is pulling back from its leadership role in seeking diplomatic rather than military solutions to the world's crises.

"I would like to see people on both sides of the aisle not just talking about this. I think we all need to be doing more about this," Booker said.

Booker, who helped lead a filibuster last year to force Senate Republicans to take up legislation to prevent suspected terrorists from buying weapons, said only a mobilized American public will force passage of gun safety legislation in the wake of the Las Vegas massacre in which at least 58 people were killed.

"The opposite of justice is not injustice, it's indifference, it's inaction," Booker said. "We as Americans who believe this passionately have to get engaged, have to start pressuring, have to start pushing, have to start fighting."

Jonathan D. Salant may be reached at jsalant@njadvancemedia.com. Follow him on Twitter @JDSalant or on Facebook. Find NJ.com Politics on Facebook.