The House intelligence committee will soon receive top-secret documents that investigators expect to reveal whether private communications of the president-elect and his transition team were improperly gathered.

Rep. Devin Nunes (R., Calif.), chairman of the oversight panel, is pressing ahead with an investigation into unauthorized disclosures of intelligence that revealed the identities of Americans inadvertently caught up in foreign electronic surveillance, congressional aides said.

Nunes this week brushed off harsh Democratic-led criticism of recent briefings he gave to President Donald Trump and House Speaker Paul Ryan (R., Wis.) based on disclosures of improper electronic spying provided by an intelligence community whistleblower.

Documents shown to Nunes revealed what appears to be electronic spying on communications of the Trump presidential transition team, including the president-elect, between November and January during a foreign spying operation.

House Democrats and major news outlets have ignored or downplayed the alarming assertions of unauthorized spying and leaks of highly classified electronic intelligence.

Instead, critics who in the past have decried unauthorized electronic surveillance by the National Security Agency have focused on unconfirmed allegations of Russian government collusion with Trump aides during the 2016 election.

Nunes expects the new NSA documents to help answer questions about how and why the identities of Americans were "unmasked" in secret intelligence reports and widely disseminated throughout government during the last days of the Obama administration, the committee aide said.

The identification of Americans in the reports and their dissemination within government is raising questions among investigators about whether the Obama administration misused foreign intelligence as part of a political spying operation against the incoming Trump transition team.

The NSA intercepts are expected to be supplied to the committee this week. They were requested by Nunes and ranking member Rep. Adam Schiff (D., Calif.) two weeks ago in a letter to the FBI, CIA, and NSA.

The committee leaders stated in the letter that recent press reports appeared to be based on unauthorized intelligence disclosures that violated spy agency rules designed to guard Americans' privacy rights.

"We're still waiting to get information back from NSA, CIA, and FBI on unmasking," a committee aide said of the process to identify Americans in foreign electronic surveillance reports.

"We've gotten some information from NSA, very little from CIA, and nothing from FBI. We're expecting a new tranche [of documents] from NSA very soon," he added.

The aide dismissed as false recent press reports asserting the House probe is floundering.

Materials provided to the committee so far do not explain who ordered the unmasking of Americans' identities in the foreign intelligence reports or why they were widely disseminated.

The Nunes-Schiff letter from March 15 asked for details of policies on identifying Americans, the total number of Americans unmasked between June and January, and who requested the names of Americans redacted in the reports.

NSA is required to black out the identities of Americans in raw foreign intelligence reports. Identities are only unmasked when there are indications of terrorist or criminal activity in the intercepts.

The House committee put off two hearings scheduled for this week, including a return visit by FBI Director James Comey and NSA Director Adm. Mike Rogers.

Comey and Rogers testified at an open committee hearing March 20 that there was "no information" to support claims by Trump in tweets that his transition team had been improperly "wiretapped" prior to Jan. 20.

The committee is expected to question both officials in the near future about why they were apparently unaware of the recently discovered intelligence reports read by Nunes at a White House meeting shortly after the March 20 hearing.

A second hearing scheduled for this week also was postponed. That session was meant to publicly question three Obama administration officials about electronic surveillance.

The committee plans to hear from former Director of National Intelligence James Clapper, former CIA Director James Brennan, and former Acting Attorney General Sally Yates, who was fired by Trump in January, when that hearing is rescheduled, possibly as soon as next week.

House investigators expect to question the former officials about their knowledge of electronic surveillance of Trump aides' communications and whether the former officials may have been the source for news stories about the secret intelligence.

White House National Security Adviser Michael Flynn was forced to resign after his identity was unmasked in intercepted communications with Russian Ambassador Sergey Kislyak that were leaked to the press. The conversations revealed Flynn had discussed U.S. sanctions on Russia in conversations, which he failed to disclose to Vice President Mike Pence prior to a Sunday talk show appearance.

The New York Times reported Thursday that White House officials Ezra Cohen-Watnick, intelligence director for the National Security Council staff, and Michael Ellis, a lawyer in the White House Counsel's Office and a former counsel to House intelligence committee, assisted Nunes in accessing the intelligence reports.

House investigators also were alerted to comments this week by Evelyn Farkas, an Obama administration deputy assistant defense secretary, who suggested on MSNBC that the Obama administration was surveilling the Trump team prior to inauguration.

Farkas, who left the Pentagon in October 2015, said that after Trump was elected she urged former colleagues in the administration and in Congress to "get as much information as you can, get as much intelligence as you can before President Obama leaves the administration because I had a fear that somehow that information would disappear with the senior [Obama] people who left, so it would be hidden away in the bureaucracy."

"If the Trump folks found out how we knew what we knew about the Trump staff's dealings with Russians, that they would try to compromise those sources and methods, meaning would no longer have access to that intelligence," Farkas said.

Farkas said she was "very worried" that "not enough was coming out into the open, and I knew that there was more."

"We have very good intelligence on Russia," Farkas said. "So then I had talked to some of my former colleagues and I knew that they were trying to help get information to the [Capitol] Hill. That's why you have the leaking."

Later, Farkas told WGBH television that the published reports on Trump aides' links to Russia were "smoke" and that once Trump was in the White House he would become custodian of all classified information. Farkas wanted Congress to get access to that information.

"So all I was saying to the Obama people and the people on the Hill was, make sure you share the data, the facts, whatever facts you have on this. And it wasn't advocating for anybody tapping, leaking, spying, anything of that nature," she said.

Reached by email, Farkas denied having knowledge of intelligence regarding ties between Russians and Trump aides, and said she had been responding to press reports about the connections.

Farkas' comments reflected those of anonymous former American officials who told the New York Times the Obama administration after November had "scrambled" to spread information within government about Russian election meddling and possible ties between Trump aides and Russians.

The March 1 Times report stated that "American intelligence agencies had intercepted communications of Russian officials, some of them within the Kremlin, discussing contacts with Trump associates."

The Times report also said U.S. intelligence agencies pushed to process "as much raw intelligence as possible into analyses, and to keep the reports at a relatively low classification level to ensure as wide a readership as possible across the government."

If accurate, that could explain how the identities of Americans were unmasked and disseminated in the classified reports seen by Nunes.

Angelo M. Codevilla, a former staff member of the Senate Intelligence Committee and an expert on electronic surveillance, said it is impossible to distinguish between "intended collection" and "incidental collection" of the kind described by Nunes.

The issue was among the most debated topics when the Senate intelligence committee drafted the Foreign Intelligence Surveillance Act (FISA) in 1978.

FISA is up for renewal this year. Allegations of improper electronic surveillance under the act could influence congressional debate on any new legislation.

"It was always clear that someone intent on ‘wiretapping' an American target could do so under FISA by piggybacking on a foreign one," Codevilla said.

Before computer servers, such abusive secondary spying on Americans was difficult technically and legally.

"No longer," Codevilla said. "The easy conflation between intended and incidental collection is the reason why we went to such lengths to describe ‘minimization procedures.' But violating these with impunity has always been child’s play."

Codevilla said incidental electronic spying can be used as an excuse since modern encryption technology prevents electronic spying on diplomatic targets through traditional and widely used capture-and-sort electronic communications collection methods.

"Virtually all of it is by highly targeted, very high tech bugging," he said. "And Internet servers are the fattest contemporary targets for electronic surveillance."

The House investigation has been marked by partisan infighting, with Democrats on the committee charging Nunes has compromised the inquiry by contacting the president. Schiff, the ranking committee member, has called for an independent investigation. Others have called on Nunes to recuse himself.

Nunes has rejected the Democrats' charges and continues to press ahead, the committee aide said.

The Democrats' criticism is unusual. In recent years, Democratic lawmakers have been critical of alleged improper NSA surveillance. Now that Nunes is focusing on the apparent improper surveillance of the Trump transition team, the Democrats appear uninterested in the issue.

Sen. Ron Wyden (D., Ore.), perhaps Capitol Hill's most outspoken opponent of electronic surveillance as a threat to Americans' privacy, has been silent on Nunes' disclosures of improper surveillance.

Wyden told the Washington Post that Nunes' statements appear to reveal classified information and were a "serious concern."

"With regard to the substance of his claims, I have no idea what he is talking about," Wyden said.

A spokeswoman for Wyden did not return emails seeking comment.