In the first open Senate Intelligence Committee hearing following FBI Director James Comey’s shocking ouster, Comey’s temporary successor said the bureau’s work investigating alleged connections between the Trump campaign and the Russian government will continue, and he will blow the whistle if the White House attempts to silence or influence the investigation going forward.

“You cannot stop the men and women of the FBI from doing the right thing, protecting the American people and upholding the Constitution,” Acting FBI Director Andrew McCabe asserted.

The committee’s top Democrat, Sen. Mark Warner (D-VA), challenged McCabe directly on whether he will report any future attempted interference to the committee.

“Mr. McCabe: While we don’t know how long you will be acting as FBI Director, my first questions for you, even in this public setting, will be for you to assure the Committee that if you come under any political influence from the White House or others to squash this investigation, or impede it in any way, that you will let this Committee know,” Warner said.

When McCabe answered that he would sound the alarm if that meddling came to pass, Warner responded, “It’s critically important that we have that assurance.”

Some Republicans on the committee, including Sen. Marco Rubio (R-FL), pressed the same point, asking McCabe: “Has the dismissal of Mr. Comey in any way impeded, interrupted, stopped or negatively impacted any of the work, any investigation, or any ongoing projects at the Federal Bureau of Investigation?”

McCabe replied that “there has been no effort to impede our investigation to date,” assuring the senators that “the work of the men and women of the FBI continues despite any changes in circumstance.”

Later, in response to a question from Sen. Ron Wyden (D-OR), McCabe promised that he will not give President Trump updates on investigations that concern him and his associates—which Trump alleged Comey had done in his termination letter.

The official White House justification for Comey’s termination was his mishandling of the investigation last year into Hillary Clinton’s use of a private email server. But reports have trickled out since Tuesday documenting President Trump’s anger over both the FBI’s investigation into Russia’s intervention in the 2016 election as well as Comey’s refusal to support the Trump’s bogus assertion that former President Barack Obama ordered a wiretap of his phone.

This post has been updated.