(CNN) The House Judiciary Committee chairman said Wednesday that his panel would subpoena special counsel Robert Mueller's final report if William Barr, President Donald Trump's nominee for attorney general, does not release it to the public.

"If necessary, our committee will subpoena the report. If necessary, we'll get Mueller to testify," Rep. Jerry Nadler, a New York Democrat, told CNN's Anderson Cooper on "Anderson Cooper 360." "The American people need the information here."

Mueller is investigating Russian interference in the 2016 campaign and possible collusion between Trump associates and Russians during the 2016 presidential campaign.

Barr was nominated by the President after Trump fired his last attorney general, Jeff Sessions, in November. The President had repeatedly and publicly criticized Sessions after he recused himself from overseeing Mueller's investigation. Matt Whitaker was then appointed the acting attorney general.

Barr appeared before the Senate Judiciary Committee earlier this week for his confirmation hearing and pledged to release "as much as I can" of Mueller's findings to the public and to provide the special counsel with the resources and time to finish the job.

He said he would not terminate Mueller without good cause and would notify Congress if he denied a major request during the investigation. Barr also said he would resign "if someone tried to stop a bona fide, lawful investigation to try to cover up wrongdoing."

Barr sympathized with the President and said it is "understandable" that someone would view an investigation as a "witch hunt" -- as Trump has repeatedly called the Russia probe -- if they felt they were wrongly accused. But Barr also defended the special counsel and said Mueller would not be involved in a "witch hunt."

Nadler told CNN on Wednesday that Barr is "obviously there to protect the President" and the nominee had "made it pretty clear he would not release the Mueller report to the public, and that's unacceptable." He said Barr had made it clear he would "only release certain information -- that he was going to be the judge of that."

"The public needs all the facts," Nadler said, "and we can't have it filtered through someone who may be very partisan."