WASHINGTON -- Former White House chief strategiston Tuesday refused to answer a broad array of queries from the House Intelligence Committee about his time working for President Trump, provoking a subpoena from the panel's Republican chairman. The ranking Democrat on the committee, U.S. Rep. Adam Schiff (D-Calif.), alleged Tuesday that Bannon refusal to answer questions came as an order from the White House.
Bannon's interview was closed to the public. Video was captured of Bannon walking toward a vehicle following the hearing, Reuters reports.
The development brought to the forefront questions about White House efforts to control what the former adviser tells Congress about his time in Trump's inner circle and whether Republicans on Capitol Hill would force the issue in light of the newly issued subpoena from the GOP-controlled panel.
The congressional subpoena came the same day The New York Times reported that Bannon - a former far-right media executive and recently scorned political adversary of the president's - has beento testify before a federal grand jury.
With the issuance of Mueller's subpoena, Bannon became the highest-ranking person who served in the Trump White House to be called before a grand jury as part of the special counsel's investigation.
By itself, the move doesn't confirm that Mueller is presenting evidence to support future criminal charges. But it does show that Mueller is still actively using a grand jury as he probes the actions of Trump, his family and his staff during the campaign, presidential transition and the early months of the administration.
Congressional officials declined to say whether Bannon disclosed Mueller's subpoena during an all-day, closed-door interview with members of the House Intelligence Committee.
The members grilled Bannon as part of the committee's investigation into Russian election inference. Lawmakers also wanted answers from him about Trump's thinking when he fired FBI Director James Comey.
But Bannon refused to answer questions about that crucial period, prompting the committee's chairman, Rep. Devin Nunes of California, to issue the subpoena, said Nunes spokesman Jack Langer.
Democratic Rep. Jim Hines told CNN that Rep. Mike Conaway, the Texas Republican leading the committee's Russia probe, decided "expansive claim of executive privilege doesn't apply."
Late Tuesday after the interview concluded, Schiff said Bannon was under a "gag order by the White House." Schiff said the committee plans to call Bannon back for a second interview.
Schiff said Bannon's attorney said he would not answer any questions "concerning any discussions, meetings, conversations, that took place either during the transition or during his time in the administration," according to Reuters.
A spokeswoman for Bannon did not respond to multiple requests for comment Tuesday afternoon.
At the White House, press secretary Sarah Huckabee Sanders said "no one" had encouraged Bannon not to be transparent during questioning but there's a "process of what that looks like."
"As with all congressional inquiries touching upon the White House, Congress must consult with the White House prior to obtaining confidential material. This is part of a judicially recognized process that goes back decades," Sanders told reporters.
A White House official said the president did not seek to formally exert executive privilege over Bannon - a move that would have barred him from answering certain questions. The official said the administration believes it doesn't have to invoke the privilege to keep Bannon from answering questions about his time in the White House. The official spoke on condition of anonymity to discuss internal deliberations.
The House committee had planned to press Bannon on "executive actions" taken by Trump that have drawn interest from congressional investigators prying into ties between Trump's campaign and Russian operatives, said another person, who wasn't authorized to speak on the record about the closed-door session and spoke on condition of anonymity.
Those key elements bear directly on the criminal investigation led by Mueller, who is charged with investigating ties between the Trump campaign and Russia and whether the president obstructed justice by firing Comey or by taking other actions to thwart investigators.
The focus on Bannon follows his spectacular fall from power after being quoted in a book saying that he sees the president's son and others as engaging in "treasonous" behavior for taking a meeting with Russians during the 2016 campaign.
In Michael Wolff's "Fire and Fury," Bannon accuses Donald Trump Jr., Jared Kushner and former Trump campaign chairman Paul Manafort of essentially betraying the nation by meeting with a group of Russian lawyers and lobbyists who they believed were ready to offer "dirt" on Democratic candidate Hillary Clinton.
More recently, Bannon has said he was not referring to Trump Jr. but rather to Manafort. Wolff stands by his account.
After the book's release, Trump quickly disavowed "Sloppy Steve Bannon" and argued extensively there was no evidence of collusion between his presidential campaign and operatives tied to Russian President Vladimir Putin. Bannon apologized a few days later but was stripped of his job leading the pro-Trump news site Breitbart News.
Bannon last year had largely avoided the scrutiny of congressional investigators, who instead focused much of their energy on trying to secure interviews with top witnesses like Manafort and former national security adviser Michael Flynn.
But Bannon played a critical role in the campaign, the presidential transition and the White House - all periods of time now under scrutiny from congressional investigators looking for possible evidence of a connection between Trump's operations and Russia.