Flynn's plea, Warner said, "comes on the heels of a new report about the President's efforts to silence the independent, bipartisan Senate investigation into ties between Trump associates and Russian Federation". "Members of Congress from both parties must make clear that those actions would be fundamentally unacceptable and incompatible with the rule of law".
Flynn's plea is "a very big deal", said Gerald Lefcourt, a leading criminal defense attorney.
Flynn appeared in court after Mueller said in a court document filed on Thursday that the ex-national security adviser "did willfully and knowingly make materially false, fictitious and fraudulent statements" to the Federal Bureau of Investigation when questioned in January 2017 in Washington, about his contacts with Russian officials.
Read Schiff's full statement below, followed by Warner's full statement. Former FBI Director James Comey, whose firing in May precipitated the appointment of Mueller as special counsel, has said Trump had asked him in a private Oval Office meeting to consider ending the investigation into Flynn.More news: New Google App Could Help You Save Data
In a hearing before US District Judge Rudolph Contreras at a Washington federal courthouse on Friday, Flynn admitted he made false statements to the FBI about his contacts with then Russian Ambassador to the US Sergey Kislyak, Efe news reported.
In a January 24 interview with investigators, Flynn denied having asked Kislyak to moderate Russia's response to new sanctions and the expulsion of 35 Russian diplomats, announced by Obama in retaliation for Moscow's interference in the 2016 election.
"My guilty plea and agreement to co-operate with the Special Counsel's Office reflect a decision I made in the best interests of my family and of our country".
Our investigation in Congress is not only looking at the actions of individuals affiliated with the Trump campaign, but is also examining the broader issues of how the Russians worked to undermine our election and what steps we as a nation can take to harden our electoral process in future.
It is generally hard to pinpoint a single reason when the stock market rises or falls, but one analyst told Bloomberg that thanks to the Flynn news, investors "kind of have the rug jerked out of the Trump trade", a stock market bet that the administration would pursue more business friendly policies.More news: Vaccines and aid workers arrive by plane in Yemen after blockade
Flynn is the fourth former Trump associate to face charges in the investigation, the first who actually served in Trump's White House.
Meanwhile, let it sink in: Already, Trump's chief national security aide, his campaign manager and his deputy campaign manager have all been indicted on criminal felonies.
Friday's news made clear that Trump's inner circle, if not the president himself, are increasingly under threat by Mueller's investigation. It is part of an alarming pattern in which the President has already fired the FBI Director; pressured the Attorney General and top US intelligence officials to interfere with an ongoing investigation; and contemplated issuing pardons for his associates or firing the special counsel, according to numerous press reports.More news: Raiders' Michael Crabtree, Broncos' Aqib Talib ejected after fight