The director of national intelligence and the director of the National Security Agency refused Wednesday to say whether President Donald Trump had asked them to get former FBI Director James B. Comey to curtail the bureau’s Russia investigation.

A series of recent news reports have fueled questions about whether the White House attempted to enlist senior U.S. intelligence officials to downplay the FBI’s probe into possible Trump campaign ties with Russia.

Testifying before the Senate Intelligence Committee, Director of National Intelligence Dan Coats declined to discuss his conversations with the president, saying it would be inappropriate to do so. He did say, however, that generally he has “never felt pressured in any way to shape intelligence in a political way or in relationship to an ongoing investigation.”

Adm. Michael S. Rogers, the NSA director, also refused to talk about his interactions with the president, but he did offer a line that he referred back to repeatedly over the course of the hearing.

“In the three-plus years that I have been the director of the National Security Agency, to the best of my recollection, I have never been directed to do anything I believe to be illegal, immoral, unethical or inappropriate,” Rogers said. “And to the best of my recollection, during that same period of service, I do not recall ever feeling pressured.”

The Washington Post reported late Tuesday that Trump had asked Coats if he could convince Comey to get the bureau to lay off its investigation into the president’s first national security adviser, Michael Flynn.

Flynn resigned in February for misleading senior administration officials about his contacts with the Russian ambassador during the presidential transition.

Coats viewed the request as inappropriate and declined to intervene, according to the Post.

Earlier media reports stated that Trump had asked Coats and Rogers to publicly deny the existence of evidence indicating collusion between the Trump campaign and Russia.

In his opening statement, the top Democrat on the committee, Sen. Mark Warner of Virginia, said that if the recent reports about White House efforts are true, “it would be an appalling and improper use of our intelligence professionals — an act that could erode the public’s confidence in our intelligence institutions.”

“Any attempt by the White House or even the president himself to exploit this community as a tool for political purposes is deeply, deeply troubling,” Warner said.

Wednesday’s hearing comes 24 hours ahead of one of the most highly anticipated congressional hearings in years, when Comey testifies before the same committee.

Comey reportedly told Attorney General Jeff Sessions in February that he did not want to be left alone with the president, according to The New York Times. Comey made his request to Sessions the day after Trump allegedly asked Comey to drop the FBI’s investigation into Flynn.