Rhode Island Sen. Sheldon Whitehouse, the top Democrat on the Senate Environment and Public Works Committee, said recent layoffs at EPA, coupled with Zeldin's comments about sharp spending cuts, show he had no intent to follow through on a pledge during his confirmation hearing to work collaboratively with EPA's staff.

The president also said EPA has found "a lot of people that didn't exist" at the agency, but did not elaborate.

The White House on Thursday walked back President Donald Trump's claim the day before that the Environmental Protection Agency plans to cut 65% of its workforce, saying the environmental regulator plans to cut its spending by 65%.