Donald Trump and Barack Obama. REUTERS/Carlos Barria President Barack Obama in November warned Donald Trump, then the president-elect, against hiring retired Gen. Michael Flynn as his national security adviser, three Obama administration officials told NBC on Monday.

The Associated Press and CNN have also reported that Obama discouraged Trump from appointing Flynn.

The reports said Obama, who fired Flynn as head of the Defense Intelligence Agency about two years after appointing him to the position in 2012, warned Trump about Flynn during a 90-minute conversation they had at the White House on November 10, two days after Trump's election victory.

Trump asked Flynn in February to resign as national security adviser after reports surfaced that Flynn misled Vice President Mike Pence about his discussions with Russia's ambassador, Sergey Kislyak, before Trump took office, including about US sanctions on Russia.

Trump and the White House have in recent days attempted to shift the blame for Flynn to the Obama administration.

Trump told Fox News on April 28 that Flynn was "already approved by the Obama administration at the highest level" when he was hired as national security adviser in January. He doubled down on that claim on Monday morning, tweeting that Flynn "was given the highest security clearance by the Obama administration — but the fake news seldom likes talking about that."

White House press secretary Sean Spicer said during a press briefing on Monday that "it's true that President Obama made it known [to Trump] that he wasn't a fan of General Flynn's." Spicer added that Obama would not have been Flynn's "fan," given that Flynn had been openly critical of Obama. He noted that Obama didn't take steps to revoke Flynn's security clearance after he was asked to resign from the DIA.

Flynn was forced out of the DIA in 2014 because his vision for the agency "was seen as disruptive," a former Pentagon official who worked closely with Flynn told The Washington Post at the time.

"Mr. President: You failed to vet Flynn, hired him, and only fired him once his lies became public," Democratic Rep. Adam Schiff tweeted on Monday. "Which part of that is Obama's fault?"

Former National Security Adviser Michael Flynn. Thomson Reuters

Flynn has come under intense scrutiny for failing to disclose his conversations with Kislyak during the transition period. He also did not disclose payments from Russia's state-owned news agency, Russia Today, when he was renewing his security clearance in January 2016.

Flynn also lobbied on behalf of a Turkish businessman with ties to the country's government between August and November, but he did not register as a foreign agent with the Justice Department until earlier this year.

Revelations about these omissions have sparked questions about why Flynn, who was a top Trump surrogate during the campaign, was not vetted more carefully by Trump administration officials before being brought into the White House.

"Why would you rerun a background check on someone who was the head of the Defense Intelligence Agency that had and did maintain a high-level security clearance?" White House press secretary Sean Spicer said during a press briefing late last month.

Many national-security and intelligence experts have argued, however, that in light of Flynn's lobbying work throughout 2016 and ouster in 2014, he should have been subject to more scrutiny before he was elevated to such a high-level national-security position at the White House.

The news of Obama's warning to Trump comes hours before former Deputy Attorney General Sally Yates is expected to testify before a Senate judiciary subcommittee about reports that she told the White House in January about what Flynn and Kislyak spoke about in the weeks before Trump was inaugurated.

Yates is expected to publicly confirm those reports for the first time — and deliver a rebuke to the Trump administration in the process.

"Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to" the White House counsel, Trump tweeted on Monday morning.

Trump has said he was not aware Flynn had discussed the issue of US sanctions with the Russian ambassador.

According to CNN, however, Yates plans to say she told the White House about Flynn's conversations with Kislyak and that he was misleading Pence and therefore susceptible to Russian blackmail.

Yates reportedly told White House counsel Don McGahn that she had "serious concerns" about Flynn, but Flynn was not asked to resign until February 13, at least two weeks after Yates visited the White House.