Numerous private citizens connected with President Donald Trump's campaign team were "unmasked" in intelligence information swept up in "incidental collection" that House Intelligence Committee Chairman Devin Nunes secretly viewed last week, according to news reports on Friday.

The names were exposed by an individual who is not in the FBI, but is "very well known, very high up, very senior in the intelligence world," a source told Fox News.

President Donald Trump responded to the story on Saturday:

Wow, @FoxNews just reporting big news. Source: "Official behind unmasking is high up. Known Intel official is responsible. Some unmasked.... — Donald J. Trump (@realDonaldTrump) April 1, 2017

..not associated with Russia. Trump team spied on before he was nominated." If this is true, does not get much bigger. Would be sad for U.S. — Donald J. Trump (@realDonaldTrump) April 1, 2017

Nunes, the California Republican who is under fire for seeing the information but not sharing it with his committee, now knows who the individual is, the source told Fox.

"The main issue in this case, is not only the unmasking of these names of private citizens, but the spreading of these names for political purposes that have nothing to do with national security or an investigation into Russia's interference in the U.S. election," a congressional source told Fox.

The Foreign Intelligence Surveillance Act only allows for individuals to be revealed in data collected incidentally when it is critical to the intelligence — and such information is only collected on U.S. residents who communicate with foreign targets.

But in this case, according to Fox, the names of private citizens connected to the Trump campaign were revealed — and it was not out of national security concerns.

"Unmasking is not unprecedented, but unmasking for political purposes . . . specifically of Trump transition team members . . . is highly suspect and questionable," an intelligence source told the network. "Opposition by some in the intelligence agencies who were very connected to the Obama and Clinton teams was strong.

"After Trump was elected, they decided they were going to ruin his presidency by picking them off one by one."

In addition, the incidental collection began before Trump became the Republican presidential nominee at last summer's national convention last July.

Nunes has known about the unmasking of the private citizens since January, before Trump kicked off the controversy with his March 4 tweets alleging that former President Barack Obama had ordered wiretaps on his telephones in New York during the campaign last year.

Two intelligence sources approached Nunes about the unmasking, Fox reports, telling the congressman who was responsible and at least one of the names that had been exposed.

The sources also gave Nunes the serial numbers of reports that documented the activity.

But when the congressman asked intelligence agencies to see the reports, he was "stonewalled," Fox reports.

Nunes finally viewed the information last week, but only at one location that would not compromise the identities of the sources: the Old Executive Office Building on the White House grounds.

The location has a secured area where classified or similar information can be viewed, according to the report.

The White House did not tell Nunes that the reports existed, only helping him get access to them, the sources told Fox.

In addition, they were not the individuals named in a report by The New York Times on Thursday as helping Nunes obtain the information, according to Fox.

On March 22, Nunes told reporters that information was "incidentally collected" by U.S. spy agencies on Trump's transition team — and those names were included in various intelligence reports.

He then briefed President Trump on the data, drawing fire from Democrats that included Vice Chairman Rep. Adam Schiff, also of California for not first providing the information to panel members.

Nunes apologized the next day, saying that he briefed Trump because the data had no connection to Russia or its investigation of Moscow's role in the election.

Schiff was expected to view the information in a classified setting at the White House on Friday.