One puzzling part of the dramatic announcement by Nunes was that the subject matter did not relate to the probe into election meddling by Russian Federation in 2016, or ties between Russian Federation and the Trump Campaign.
Speaking to reporters on Friday, Mr Nunes said that he had invited Federal Bureau of Investigation director James Comey and National Security Agency (NSA) chief Adm Mike Rogers to provide further testimony at a closed intelligence committee session.
Among other things, the letter demands to know who in USA government requested or authorized the unmasking of anyone associated with the Trump campaign.
That lead to accusations that Nunes was providing cover for Mr. Trump's unproven wiretapping claims. The intercepts were not Russia-related, Nunes said.
Nunes said at a news conference he discovered the accounts of Trump conversations when he was reviewing intelligence reports and said the information was not related to Russian Federation, which is accused of interfering in the USA election.
The question is why was it unmasked if it was unmasked, and then who was on the dissemination list and why was the list so broad? he added. The NSA document production is expected to produce more intelligence than Nunes has so far seen or described - including what one source described as a potential "smoking gun" establishing the spying.
FBI Director James Comey announced Monday that his agency was investigating the relationship, testifying that the FBI came to believe that Russian Federation was using "active measures" to hurt the Clinton campaign and help the Trump campaign.
However, Nunes said he alerted House Speaker Paul Ryan about the information before he headed to the White House.
There has been "strong pushback from the White House" on the investigation, said the committee's ranking member Republican Adam Schiff (D-AC). "The chairman will need to decide whether he is the chairman of an independent investigation into conduct which includes allegations of potential coordination between the Trump campaign and the Russians or he's going to act as a surrogate of the White House because he can not do both", Schiff said.
Current and former officials say that it's possible that Trump or his aides were picked up "incidentally" by surveillance, if a foreign diplomat or other target called them or emailed them.
To the extent that Americans are mentioned in these documents, those names are supposed to be blacked out in any intelligence report that is circulated around the government, unless the identities are needed to understand the intelligence.