(CNN) The House intelligence committee issued subpoenas Wednesday to former national security adviser Michael Flynn and President Donald Trump's personal lawyer, Michael Cohen, as part of the probe into Russian activity during the 2016 election.
The panel also issued subpoenas for documents related to "unmasking" of names separate to the Russia investigation.
The subpoenas, the first from the House panel, seek their testimony, as well as documents from their businesses. The committee issued a total of seven subpoenas Wednesday -- four related to the Russia investigation and three seeking details of "unmasking" of US residents by former national security adviser Susan Rice, former CIA Director John Brennan and former US ambassador to the United Nations Samantha Power, a source said Wednesday.
"As part of our ongoing investigation into Russian active measures during the 2016 campaign, today we approved subpoenas for several individuals for testimony, personal documents and business records," Reps. Michael Conaway, R-Texas, and Adam Schiff, D-California -- the co-leaders of the House investigation -- said Wednesday in a statement.
"We hope and expect that anyone called to testify or provide documents will comply with that request, so that we may gain all the information within the scope of our investigation. We will continue to pursue this investigation wherever the facts may lead," they added.
The subpoenas come a day after Cohen said he would not cooperate with congressional investigators and amid turmoil inside the House investigation itself, as lawmakers wrangle with the role of House Intelligence Chairman Devin Nunes, R-California, in the probe.
A congressional source familiar with the committee's probe tells CNN that the House intelligence committee issued a total of seven subpoenas today. Four of the subpoenas were issued on the Russia probe and three others were issued seeking information on "unmasking," the identification of US citizens picked up during surveillance of foreign nationals.
Trump tweeted Thursday morning that "the big story is the 'unmasking and surveillance' of people that took place during the Obama administration," a point he's made previously as the investigation into alleged ties between his campaign and Russia has accelerated.
A source close to Flynn said Tuesday that the former national security adviser would comply with a series of Senate subpoenas issued for documents from Flynn and his businesses.
Nunes' role in the issuing of subpoenas has been a sore point behind the scenes in the House investigation ever since he announced he was recusing himself from leading the Russia investigation.
The three subpoenas for information about Rice, Brennan and Power's roles in revealing names reflects Nunes' public statements wanting more information about who may have unveiled the names of Trump transition aides caught on US-monitored lines talking with foreign officials.
Nunes has unilateral authority on the House intelligence committee to issue subpoenas, although the committee's rules recommend he consult with the top Democrat as well, who is currently Schiff.
"If the reports are accurate, subpoenas related to the 'unmasking' issue would have been sent by Nunes acting separately from the committee's Russia investigation," said a senior aide on the committee. "This action would have been taken without the Democrats' agreement. Any prior requests for information would have been undertaken without the Democrats' knowledge."