Michael Flynn. AP Photo/Carolyn Kaster

The House Intelligence Committee issued seven subpoenas Wednesday as part of its investigation into Russian interference in the 2016 election, including subpoenas to former National Security Adviser Michael Flynn and President Donald Trump's personal lawyer, Michael Cohen.

"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," said Reps. Mike Conaway and Adam Schiff, the top Republican and Democrat involved in the investigation.

"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 said.

Four of the seven subpoenas were related to the committee's investigation into Russian interference in the election, according to The Wall Street Journal. Flynn's lobbying firm, Flynn Intel Group, was also subpoenaed, as was Cohen's firm, Michael D. Cohen & Associates.

Flynn was forced to resign when it was reported in February that he had spoken to the Russian ambassador about US sanctions and then misled Vice President Mike Pence about his contacts. Flynn reportedly plans to invoke his Fifth Amendment rights in response to a separate subpoena issued by the Senate Intelligence Committee. Cohen's subpoena comes after he declined a request to provide information and documents related to his contacts with Russian officials.

Cohen told ABC on Tuesday that he "declined the invitation to participate, as the request was poorly phrased, overly broad, and not capable of being answered." He later told CNN that the lawmakers "have yet to produce one single piece of credible evidence that would corroborate the Russia narrative."

Former National Security Adviser Susan Rice. Chip Somodevilla/Getty Images

The other three subpoenas relate to questions around why Obama administration officials "unmasked" and distributed the names of Trump associates in classified intelligence reports.

The Journal reported that those subpoenas were issued to the CIA, FBI, and NSA and are seeking information related to unmasking requests made by former National Security Adviser Susan Rice, former CIA director John Brennan, and former UN ambassador Samantha Power.

Unmasking requests are not uncommon, said Charles Price, a former FBI agent who worked at the bureau for nearly three decades. "They're really not that big a deal."

"The identities of US persons may be released under two circumstances: 1) the identity is needed to make sense of the intercept; 2) if a crime is involved in the conversation," Robert Deitz, a former senior counselor to the CIA director and former general counsel at the National Security Agency, told Business Insider in April.

The subpoenas related to unmasking requests were reportedly made by Republicans on the committee interested in examining whether the requests were politically motivated, The Journal reported.

In April, it emerged that Rice tried to learn the identities of Trump officials whose names were incidentally collected during routine intelligence-gathering operations.

After news of Rice's request broke, she denied accusations that she had leaked the names of unmasked Trump officials to media outlets.

"I leaked nothing, to nobody, and never have and never would," Rice said.

"I don't take much" from the subpoenas issued related to unmasking requests, Deitz said. He added that he saw them as a concession to Trump supporters on the committee and that they likely wouldn't result in any damning information about Rice and other Obama administration officials.

James Comey. Zach Gibson/Getty Images

The Trump-Russia investigations, both in relevant congressional committees and within the FBI, have picked up steam over the last few weeks, following Trump's decision to abruptly fire FBI Director James Comey.

After Comey's dismissal and a number of explosive reports, Deputy Attorney General Rod Rosenstein appointed former FBI director Robert Mueller as a special counsel in charge of the FBI's investigation.

Last week, multiple reports said Trump's son-in-law and senior adviser, Jared Kushner, spoke with the Russian ambassador about setting up a back channel of communications with Russia using Russian facilities. News of his reported request indicated that the Russia investigation could reach the highest levels of Trump's White House.

On Wednesday, CNN reported that Comey plans to testify as early as next week, during which he is expected to confirm reports that Trump asked him to drop the FBI's investigation into Flynn during a February meeting. Experts say such a request could amount to obstruction of justice.