"Why did the president wait 18 days to fire Mike Flynn after the White House was informed of his conduct and warned that he was a potential target for Russian blackmail?" asked Kaitlan Collins of The Daily Caller.
Notably, Trump's own White House requested the House and Senate investigations after he took to Twitter on a Saturday morning and accused Obama of tapping the phones in Trump Tower.
On Monday, Trump tweeted that James Clapper, the Director of National Intelligence, "reiterated what everybody, including the fake media already knows- there is "no evidence" of collusion w/ Russian Federation and Trump".
Ms Yates told the hearing: "We felt like it was critical that we get this information to the White House, in part because the vice president was making false statements to the public and because we believed that General Flynn was possibly compromised". Around the same time, Politico reported that Obama personally warned Trump during the transition that Flynn was problematic.
Donald Trump has hit back angrily over new claims about his former national security adviser Michael Flynn, who resigned amid controversy over his links with Russian Federation.
Trump has repeatedly branded the issue of Russian interference "fake news" despite leaders of the U.S. intelligence community concluding that President Vladimir Putin himself was behind the meddling.
He recalled the Democrats who were swept into office with him in 2009, but lost their seats after casting votes in favour of the "Obamacare" measure.
Despite firing Flynn, Trump has tried to paint his former national security adviser as a victim of illegal leaks of classified information by Obama officials.
After he resigned from the US Defense Intelligence Agency (DIA) in 2014, Flynn became a contributor to RT, formerly known as Russia Today, the English-language mouthpiece of the Kremlin, widely considered as one of its overarching propaganda tools.More news: Audioslave and Soundgarden Frontman Chris Cornell Dies at 52, Stars React
The same year he received about United States dollars 45,000 for attending RT's gala dinner in Moscow, where he sat next to Putin. Trump's White House press secretary Sean Spicer said in response Monday that if Obama "was seriously concerned" about Flynn's connections to Russian Federation or other foreign countries, he should have withheld Flynn's security clearance.
Trump, of course, ignored Obama.
Obama gave the warning in an Oval Office meeting with Trump two days after the Republican's surprise November 8 election win.
Yates, who was sacked by President Trump on January 30, said that it is believed that the Russian government had recordings of Flynn's call. Another official said Obama's remark seemed like it was made in jest.
The warning was "based on Flynn's role as head of DIA", a former administration official told the AFP. Michael Flynn, and what Yates knew of Russian election interference.
Yates' warning about Flynn capped weeks of concern among top Obama officials, former officials told the AP. "They likely had proof of this information, and that created a compromise situation".
Former acting Attorney General Sally Yates was due before a Senate Judiciary subcommittee, where she spoke about her warnings to the White House about former national security adviser Michael Flynn's contacts with Russian Federation.
She also said that her office informed the White House of this 18 days before Flynn was sacked. Pence said in January that Flynn denied those calls involved sanctions placed on Russian Federation by the Obama administration in response to its election meddling.
The presence of her co-witness, Washington veteran and former Director of National Intelligence James Clapper, also had the effect of bolstering Yates' comments.