WASHINGTON (AP) — The House Intelligence Committee has subpoenaed former White House national security adviser Michael Flynn and former Trump campaign aide Rick Gates as part of its investigation into Russian efforts to interfere with the 2016 election.

Committee Chairman Adam Schiff said Thursday the committee is examining "deep counterintelligence concerns" raised in special counsel Robert Mueller's report and "requires speaking directly" with Flynn and Gates, who were important witnesses for Mueller's investigation.

"The American people, and the Congress, deserve to hear directly from these two critical witnesses," the California Democrat said in a statement. "We hope these witnesses come to recognize their cooperation as being with the United States, not merely the Department of Justice."

The subpoena seeks documents and testimony from both men.

Flynn admitted lying to the FBI about his conversations with the Russian ambassador to the United States and awaits sentencing. He was supposed to have been sentenced last December, but midway through the hearing, abruptly asked for it to be postponed so that he could continue cooperating with the Justice Department and earn additional credit toward a reduced sentence.

Gates pleaded guilty to conspiracy and false statement charges related to Ukrainian lobbying and political consulting he did with ex-Trump campaign chairman Paul Manafort, who's been sentenced to more than seven years in prison.