Dan Coats, the director of national intelligence, and Mike Rogers, the NSA director, refused to confirm whether President Donald Trump asked them to intervene in the FBI's probe of his campaign ties to Russia.
Coats reportedly told associates in March that Trump had attempted to enlist him in efforts to push back against the investigation of disgraced national security adviser Mike Flynn.
He told Sen. Mark Warner (D-VA), the committee's ranking Democrat, that he did not want to discuss the matter in an open hearing, but he insisted he had "never felt pressure to intervene or interfere in any way."
Warner told the intelligence official he was missing an opportunity to lay to rest media reports suggesting the president was trying to interfere in the investigation, and he said another individual would likely offer testimony about those efforts.
Former FBI director James Comey, who Trump has said he fired over the Russia probe, is scheduled to testify Thursday.
Rogers refused to discuss the specifics of any conversations he had with Trump, and he refused to tell lawmakers whether presidents typically asked questions about ongoing FBI investigations.
Trump reportedly cleared the Oval Office following a March 22 meeting to privately complain to Coats and CIA director Mike Pompeo about then-FBI director James Comey's investigation.
Afterward, Coats told other officials that Trump had asked him to get Comey to back off the investigation of Flynn and other campaign associates -- but the intelligence official declined.