The conversations reportedly involved sanctions imposed on Russian Federation by the Obama administration, although Flynn has denied that sanctions were discussed.
Trump named retired Lt. Gen. Keith Kellogg as the acting national security adviser.
A month ago, Face the Nation host John Dickerson offered the former IN governor the opportunity to clear the air: "Just to button up one question", Dickerson said, "Did any adviser or anybody IN the Trump campaign have any contact with the Russians who were trying to meddle IN the election?"
In a resignation letter, Flynn said he gave Pence and others "incomplete information" about his calls with Russia's ambassador to the U.S. The vice president, seemingly relying on information from Flynn, initially said the national security adviser had not discussed sanctions with the Russian envoy though Flynn later conceded the issue may have come up.
Former White House national security adviser Michael Flynn told Federal Bureau of Investigation agents in an interview last month that he had not discussed sanctions against Russian Federation with Moscow's US ambassador before President Donald Trump took office, the Washington Post reported on Thursday, citing current and former USA officials. He said the White House has yet to be forthcoming about whether Flynn was acting at the behest of the president or others.
"The President is clearly upset about this", Press Secretary Sean Spicer said.
"The goal is to blow up the Trump administration". Current and former USA officials interviewed by the Times declined to identify other President Trump associates contacted by the Russians.
Amid reports of widespread leaks within his administration, Trump also warned that he would clamp down on the dissemination of sensitive information, saying he had asked the Justice Department to look into the leaks.
USA lawmakers, including some leading Republicans, called for an investigation.
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A record 1.96 inches fell at Long Beach Airport, breaking the daily rainfall record of 1.81 inches set in 1980. Firefighters rescued one person from the first vehicle , and the driver got out of the second before it fell.
The revelation Flynn was personally approached by federal investigators comes one day after his resignation and similar reveals officials at the Department of Justice, including then-acting attorney general Sally Yates, believed the pre-inaugural January 26 call over sanctions had opened up Flynn to the possibility of blackmail.
California Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, said Flynn's resignation "does not end questions over his contacts with the Russians". Flynn later told officials the sanctions may have been discussed, the latest change in his account of his pre-inauguration discussions with Ambassador Sergey Kislyak.
"You can not have the national security adviser misleading the vice president and others", Ryan said.
CNN has reported that USA intelligence agencies told Trump and then President Barack Obama about Russian efforts to build up compromising financial and personal information about him last month.
The Justice Department warned the White House that the inconsistencies would leave the president's top national security aide vulnerable to blackmail from Russian Federation, according to a person with knowledge of the discussion.
The officials and others with knowledge of the situation were not authorized to discuss the matter publicly and requested anonymity. The president was informed of the warnings the same day, Spicer said.
Flynn left his post after reports that he held multiple phone calls with Russia's ambassador to the United States about sanctions on Moscow before Trump took office.
The drama over Flynn now threatens to morph into a much wider and more damaging controversy for the White House, that could involve congressional investigations and possibly shake loose even more allegations about the administration's conduct and relationship with Moscow.