The chairman of the committee, Rep. Devin Nunes (R-Calif.), has since cast the practice of "unmasking" of U.S. individuals and organizations mentioned in classified reports as an abuse of surveillance powers by the outgoing Obama administration.
Trump has argued that investigators should focus their attention on former officials leaking names from intelligence reports, rather than whether the Kremlin coordinated its activities with the Trump campaign, an allegation he has denied. "The big story is the 'unmasking and surveillance' of people that took place during the Obama administration," Trump tweeted Thursday.
According to a tally by U.S. spy agencies, the House Intelligence Committee requested five to six unmaskings of U.S. organizations or individuals related to Trump or Democratic candidate Hillary Clinton between June 2016 and January 2017. Officials familiar with the matter said that the committee's requests focused on the identities of U.S. organizations that had been hacked by the Russians in 2016. Officials declined to say how many of the requests came from Democrats vs. Republicans.
The chairman of the committee wields enormous control over the actions of its members and requests for more information from intelligence agencies. Officials said that committee rules require the chairman to sign off on the requests, even ones that are not his own.
A spokesman for Republicans on Nunes's committee declined to comment on whether the panel made any requests for unmasking.
He added, "It is standard operating procedure for the House Intelligence Committee to forward all committee members' questions from both parties to the appropriate agencies, whether or not they are answered. I refer you to committee Democrats for further questions on this subject."
Every day, U.S. intelligence agencies sweep up vast quantities of foreign communications. Sometimes, they pick up communications involving U.S. individuals or organizations. In reports based on those communications, intelligence agencies "mask" the identities of the Americans, part of an effort to protect their privacy.
Senior government officials, however, can ask spy agencies to reveal the names of Americans or U.S. organizations in the reports if they believe that doing so will help them better understand the underlying intelligence. They must have a legitimate need to know, and National Security Agency unmaskings are reviewed by the Justice Department and the Office of the Director of National Intelligence, known as the ODNI.
Some officials said that House Intelligence Committee members may not have realized spy agencies would count their requests as unmaskings. These officials said lawmakers submitted questions that intelligence officers could answer only by revealing the identities of U.S. individuals.
Nunes served subpoenas this week to the CIA, the NSA and the FBI asking for information about unmaskings requested by three former officials: national security adviser Susan E. Rice, CIA director John Brennan and U.N. ambassador Samantha Power.
On Thursday, Nunes tweeted, "Seeing a lot of fake news from media elites and others who have no interest in violations of Americans' civil liberties via unmaskings."
Democrats on the panel say they believe the latest direction of Nunes's investigation is designed to deflect attention from the Russia probe. In April, Nunes was forced to recuse himself from the committee's probe of Russia because of allegations he may have inappropriately disclosed classified information. Nunes has denied any wrongdoing.
Current and former U.S. intelligence officials say requests for unmaskings are a routine and necessary part of their national security work. After requests are made, spy agencies decide whether to provide the names. Officials say few requests are rejected because most are legitimate.
Still, senior officials know that unmaskings can be controversial and are often reluctant to submit large numbers of requests. To protect themselves from any allegations of abuse, spy agencies track unmasking requests closely.
Rice and Brennan declined to comment. During an appearance on MSNBC's "Andrea Mitchell Reports" in April, Rice denied that she sought to improperly unveil the names of Trump campaign or transition officials for political purposes. In recent congressional testimony, Brennan also has denied that he made any improper unmaskings.
Power did not immediately respond to a request for comment.
Nunes first called for his committee to investigate alleged Obama administration-era surveillance of Trump and his associates after the president, in a March 4 tweet, accused Obama of wiretapping Trump Tower. Officials said at the time that Trump's wiretap allegations were false.
On March 15, Nunes and the committee's ranking Democrat, Rep. Adam B. Schiff of California, sent a joint letter to the CIA, the NSA and the FBI asking them to provide the names of any intelligence and law enforcement agencies, as well as senior executive branch officials, who requested or authorized the unmasking of any U.S. persons or organizations between June 2016 and January 2017 related to "presidential candidates Donald J. Trump and Hillary Rodham Clinton and their associates in 2016."
While the House Intelligence Committee asked only for the names of administration officials who requested unmaskings related to Trump and Clinton, intelligence agencies responded to the request by providing a tally that included requests by lawmakers.
The tally showed several requests from the House Intelligence Committee — requests that one official said were no different than those made by Obama administration officials. "This notion that there are these politically motivated unmaskings is just nonsense," said the official.
In contrast to the committee's handful of unmasking requests, officials said the tally showed that Rice requested a single unmasking related to Trump's activities between June and January.
The Republican-led Senate Intelligence Committee made no requests for unmaskings related to either Trump or Clinton during that time frame, according to the tally.
At a House Intelligence Committee briefing in May, Rep. Trey Gowdy (R-S.C.) pressed Brennan on whether he had ever requested the unmasking of a U.S. person's identity. Brennan responded that he had.
Gowdy then pressed Brennan on whether he was aware of any requests made by any "U.S. ambassadors," a possible reference to Power.
Brennan said he was not aware of any unmasking requests by ambassadors.
According to the ODNI, last year the NSA unmasked at least 1,934 identities of U.S. persons at the request of government officials. That figure relates to a certain court-authorized program of foreign intelligence gathering inside the United States.