The House Intelligence Committee issued seven subpoenas - four are seeking information from former national security adviser Michael Flynn and President Donald Trump's personal lawyer Michael Cohen.
The Journal reports that the Senate Intelligence Committee will soon hear testimony, possibly next week, from fired FBI Director James Comey about whether President Trump asked him to "back off" investigating "Russiagate".
Cohen, who'd earlier refused a request for information saying it was "not capable of being answered", told The Associated Press on Tuesday that he would comply with subpoenas, should they be issued. Ahead of the presidential poll, thousands of hacked emails of Democratic candidate Hillary Clinton's campaign chairman, John Podesta, and the Democratic National Committee were leaked. He stepped back from the Russian Federation probe after he was accused of sharing information about the investigation with the Trump administration.
The once-uncommon practice grew steadily under President George W. Bush as policymakers received a flood of post-9/11 intelligence, according to an April report in Foreign Policy.
This is what he said on April 6 right before the House Ethics Committee announced it was investigating whether Nunes broke House rules by revealing classified information in conversations with the media about the Russian Federation investigation.
The subpoenas were expected to be delivered to retired Army General Michael Flynn, who was sacked as national security adviser by Trump in February, and the president's personal lawyer, Michael Cohen, the sources said. In March, he offered to be interviewed by the committee if he would receive immunity from prosecution in return, but congressional investigators said they would not make a deal with Flynn at that time.
The embattled head of the House Intelligence Committee Wednesday appeared to have launched an investigation of his own, this one into allegations that senior Obama administration officials improperly "unmasked" the identities of Trump associates captured communicating with foreign officials.
Mr. Nunes, it should be recalled, announced in April that he would step aside from the panel's investigation into the Russian Federation affair.
The committee's ranking Democrat, Rep. Adam Schiff of California, said Nunes approved the unmasking subpoenas without consulting the Democrats on the committee.
Three of the subpoenas seek information about how and why the names of President Donald Trump's associates were revealed and distributed within classified reports by Obama administration officials during the transition period after the election, a process known as "unmasking". But on Wednesday, he used his power as chairman to issue subpoenas related to the inquiry.
The aide argued that "temporarily stepping aside" and "recusing" are two entirely different things, and noted that Nunes still has an important job to fill as chairman of the House intelligence committee, including investigating any "unmasking" - the revealing of USA nationals swept up in routine surveillance of foreign officials - in intelligence reports.
The Guardian newspaper said on Thursday said that Nigel Farage, a Trump supporter and a leading Brexit campaigner, is a "person of interest" in the Federal Bureau of Investigation probe but has not been accused of wrongdoing.
At most, only one of the requests related to Russian Federation in any way, and the rest pertained to other countries, two of them said.
The staffer said the Democrats were informed that the unmasking subpoenas were being issued.
"You often couldn't understand what was going on unless you asked for the identity of the USA persons", once former official told Foreign Policy.
Democrats on the committee say they were not consulted on the unmasking subpoenas.