The hearing centered on a controversial piece of the Foreign Intelligence Surveillance Act, known as FISA, that provides the legal framework for collecting foreign intelligence without a warrant. The hearing was called because Congress must decide whether to reauthorize FISA in full.

Top U.S. intelligence and law enforcement officials went before a Senate committee Wednesday to talk about surveillance — but they faced a flurry of questions about President Donald Trump , as well.

In his opening statement, Coats argued that "permanent reauthorization" of FISA without amendment is "vital" to identifying threats and protecting Americans. He said that he has seen "no instances of intentional violations" of legal protections under the foreign collection provision, known as Section 702.

Coats highlighted that it does not allow targeting of U.S. citizens anywhere in the world and does not allow collection from anyone in the U.S. regardless of their nationality. He also contended that it would prove too difficult and intrusive to research how many Americans were unintentionally affected by the collection.

In a statement Wednesday, the American Civil Liberties Union argued that the Trump administration has not provided enough evidence on how many Americans are affected by Section 702. ACLU legislative counsel Neema Singh Guliani argued that it is "long overdue for Congress to finally pass reforms to curb this invasion of Americans' privacy."

But some senators seemed to want to hear more about Trump and the investigation into possible ties between his campaign and Russia than they did about FISA.

Democratic Sen. Mark Warner of Virginia asked Coats and Rogers about media reports that Trump asked them to publicly say that evidence showed that Trump's campaign did not collude with Russia. The hearing also came hours after The Washington Post reported that Coats told associates that Trump asked him if he could persuade former FBI Director James Comey to ease off a probe into former national security advisor Michael Flynn, who was fired for lying to members of the administration about his links to Moscow.

Coats and Rogers said they had never felt "pressured" to intervene in a federal investigation. However, neither official would comment specifically about whether anyone in the White House "asked" them to influence a probe.

The two men were pressed by Republican Sen. Marco Rubio of Florida to clarify: "Are you prepared to say you've never been asked?"

They said they stuck to statements they made moments earlier in the Senate hearing when questioned by Democratic Sen. Mark Warner of Virginia.

"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 believed to be illegal, immoral, unethical or inappropriate," Rogers told the Senate Intelligence Committee. "And to the best of my recollection … I do not recall ever feeling pressured to do so. "

Coats made a similar blanket denial: "In my time of service, which is interacting with the president of the United States or anybody in his administration, I have never been pressured — I have never felt pressured — to intervene or interfere in any way with shaping intelligence in a political way or in relation to an ongoing investigation."

Asked repeatedly later in the hearing by independent Sen. Angus King of Maine about his legal justification for not addressing his conversation with Trump, Coats said, "I'm not sure I have a legal basis."

GOP Sen. John McCain of Arizona called the officials' unwillingness to talk about their conversations with Trump "Orwellian."

Rosenstein was reportedly irked when the White House used a memo he wrote as justification for firing Comey. Trump subsequently contradicted his own officials and said he would have ousted Comey "regardless" of what the Justice Department said about him.

However, he would not speak publicly about the events, and referred to his statements in the public record.

Comey was fired as he was overseeing an investigation into Russian interference in the 2016 election and links between the Trump campaign and Russia.

Comey will speak publicly for the first time on Thursday about the events that led to his firing.