House Intelligence Committee Chairman Adam Schiff and Rep. Devin Nunes clashed during the third day of public impeachment hearings over the latter's line of questioning about the identity of the whistleblower.

Nunes began by asking Lt. Col. Alexander Vindman whether he spoke with anyone outside of the White House about President Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky. Vindman affirmed that he had spoken with two officials who had been cleared with "appropriate need-to-know" basis for such information, identifying senior State Department official George Kent and an "individual in the Intelligence Community."

"What agency was this individual from?" Nunes asked.

Schiff then jumped in to interrupt him, saying he wanted to "make sure that there is no effort to out the whistleblower through the use of these proceedings."

"If the witness has a good faith belief that this may reveal the identity of the whistleblower, that is not the purpose that we are here for, and I want to advise the witness accordingly," he added.

Nunes argued that it was Republicans' turn to ask questions, but Schiff and Vindman's lawyer indicated that they would not participate in efforts to out the whistleblower.

"Answer my question or plead the Fifth," Nunes told Vindman, who continued to refuse to identify the whistleblower.

While Vindman testified that he does not know the whistleblower, he has been linked to the anonymous person. The Washington Examiner has established that the pair still work together on U.S.-Ukraine policy, and Vindman may have even liaised with the whistleblower over the president's call with Ukraine.

The whistleblower's identity has not been confirmed, but career CIA analyst Eric Ciaramalla was named by RealClearInvestigations last month as the potential person behind the complaint that sparked impeachment proceedings against Trump. Ciaramella, 33, was Ukraine director on the National Security Council under former President Obama and was acting senior director for European and Russian affairs during the Trump administration.

He is now a deputy national intelligence officer for Russia and Eurasia on the National Intelligence Council and works under the director of national intelligence. Ciaramella had a close relationship with Biden during the Obama administration and attended a State Department banquet with him in 2016.

Lawyers for the whistleblower have called attempts to out their client "the pinnacle of irresponsibility" and refused to confirm or deny reports naming Ciaramella.