The House and Senate intelligence committees are expanding their investigation into the so-called “unmasking” controversy, Fox News has learned, to examine whether other candidates or lawmakers beyond President Trump’s associates were affected.

Until now, the investigation focused on how the identities and communications of Trump transition members were collected by U.S. intelligence agencies and then revealed to, and disseminated among, high-ranking members of the Obama administration.

House Intelligence Committee Chairman Devin Nunes, R-Calif., now plans to audit files from the National Security Agency and White House to determine whether identities and conversations of presidential candidates -- or members of Congress -- also were swept up during NSA surveillance of foreign leaders. He also plans to review whether Obama’s National Security Council and White House counsel collected and distributed the intelligence for reasons unrelated to foreign intelligence.

“We will be performing an accounting of all unmasking for political purposes focused on the previous White House administration,” a member of the committee told Fox News. “This is now a full-blown investigation.”

Staffers on the Senate committee told Fox News they also have expanded their investigation into whether presidential candidates were unmasked and information was misused -- and what role former National Security Adviser Susan Rice, among others, played following reports that she requested Trump-affiliated names be unmasked.

For a private U.S. citizen to be “unmasked,” or named, in an intelligence report is extremely rare and typically only done if it has some foreign intelligence value. Typically, the American is a suspect in a crime, is in danger or has to be named to explain the context of the report.

The intelligence reports that Rice and others in the administration reportedly assembled are similar to what a private investigator might piece together, congressional and U.S. intelligence sources said. In some cases, rather than documenting foreign intelligence, the files included salacious personal information that, if released, could be embarrassing or harmful to the person’s reputation, U.S. intelligence and House Intelligence Committee sources said.

These reports were then disseminated to about 20 to 30 people who had classified clearance in the Obama administration hierarchy, these sources said.

Trump, members of his family, and members of his campaign and transition teams, were likely subjects of “incidental electronic surveillance” by U.S. intelligence agencies, Fox News reported.

Sources told Fox News that names were then sent to all those at the National Security Council, some at the Defense Department, then-Director of National Intelligence James Clapper and then-CIA Director John Brennan -- as well as Rice and her former deputy Ben Rhodes, even though the names were supposed to be reported only to the initial requester.

If the names were unmasked in intelligence reports and then leaked to the media for political reasons, it could constitute criminal behavior.

Retired Lt. Gen. Michael Flynn, Trump’s initial national security adviser, is one known example of a Trump campaign official whose name was unmasked from an intelligence report and leaked to the press. While Rice hasn’t said whether she unmasked Flynn, the leak of his conversation with Russian Ambassador Sergey Kislyak where he discussed U.S. sanctions led Flynn to resign three weeks into his term.

Nunes first announced on March 22 that he’d viewed intelligence reports that contained incidental surveillance on members of the Trump team.

On Tuesday, The Washington Post reported former Trump campaign adviser Carter Page also was monitored by the FBI after the agency obtained a Foreign Intelligence Surveillance Act warrant as part of an ongoing investigation into possible links between Russian officials and members of the Trump campaign.

In a statement to Fox News, Page said he has done nothing wrong and was a political target.