Washington (CNN) Then-President Barack Obama warned President-elect Donald Trump in November against hiring retired Lt. Gen. Michael Flynn as his national security adviser , former Obama administration officials confirmed to CNN Monday. 
 
 Obama warned Trump about Flynn during their Oval Office meeting on November 10, days after Trump was elected president. 
 
 "Given the importance of the job, the President through there were better people for it, and that Flynn wasn't up for the job," a former senior Obama administration official told CNN Monday. 
 
 Other former Obama administration officials said then-Director of National Intelligence James Clapper didn't think highly of Flynn, and in fact was the person who recommended Flynn's firing as DNI in 2014. Flynn's focus was generally limited to terrorism and didn't know much about many other issues important for the national security adviser job, such as China, the officials said. 
 
 But at least one former Obama official disputed that, saying Obama's concerns were not related to the firing of Flynn from the Defense Intelligence Agency but rather in the course of the investigation into Russian interference into the 2016 election. 
 
 "Flynn's name kept popping up," according to a senior Obama administration source. 
 
 The White House confirmed later Monday that Obama raised concerns about Flynn during his Oval Office sitdown with Trump in November. 
 
 "It's true President Obama made it known he wasn't exactly a fan of Gen. Flynn's," press secretary Sean Spicer said. 
 
 He said the concerns shouldn't have come as a surprise, since Flynn was an "outspoken critic" of the Obama administration's shortcomings on foreign policy. 
 
 Spicer said if the Obama administration was "truly concerned" about Flynn, there are steps it could have taken, including suspending his security clearance. 
 
 Flynn previously served as the head of the Defense Intelligence Agency under Obama until he was reportedly forced out of the post 2014 over internal disagreements over policy and management. 
 
 Trump did not heed Obama's counsel on Flynn, bringing aboard the former military intelligence officer who supported Trump during his campaign as his national security adviser. Trump fired Flynn 24 days later when news broke of Flynn's conversations with Russian Ambassador to the US Sergey Kislyak. 
 
 News of the warning comes as former acting Attorney General Sally Yates is set to testify before Congress on Monday about the concerns she expressed to Trump administration officials about Flynn's contacts with Russian officials, namely with Kislyak. 
 
 Yates, in her role as acting attorney general, warned White House counsel Don McGahn on January 26 that Flynn was lying when he denied -- both publicly and privately -- that he discussed US sanctions on Russia with Kislyak. It wasn't until weeks later that Trump asked for Flynn's resignation, only after news surfaced that Flynn had misled Vice President Mike Pence about his conversations with Kislyak. 
 
 JUST WATCHED Trump: I feel badly for Michael Flynn Replay More Videos ... MUST WATCH Trump: I feel badly for Michael Flynn 01:31 
 
 According to five current and former intelligence officials, their concern started around the time Flynn went to Moscow for the 10th anniversary gala of the state-sponsored news agency Russia Today. At that dinner, the former high-ranking intelligence official was seated right next to Russian President Vladimir Putin. He also had contact with Kislyak after the trip. 
 
 Former US officials were highly suspicious of Kislyak and his motives, and there were concerns Flynn didn't seem to understand the dangers in the conversations, the officials said. As was reported over the weekend, even Trump's own team was concerned enough to request a CIA profile of the Russian ambassador to help illustrate to Flynn he was taking a big chance in his interactions with Kislyak. 
 
 Yates' testimony on Monday will be the first time she speaks publicly about her warnings to the White House about Flynn. 
 
 The Senate and House intelligence committees are continuing to investigate Russian interference in the 2016 election, including potential coordination between Russian officials and the Trump campaign or people close to the campaign. 
 
 Congressional investigators have so far homed in on Flynn, Carter Page, a former foreign policy adviser to the Trump campaign, and Roger Stone, who informally advised Trump during his presidential run. 
 
 While Trump asked for Flynn's resignation, he has not abandoned his former national security adviser altogether. 
 
 Trump on Monday morning sought to get ahead of Yates' testimony, taking to Twitter to deflect criticism that he or his administration should have kept Flynn out of the top national security post from the outset. 
 
 General Flynn was given the highest security clearance by the Obama Administration - but the Fake News seldom likes talking about that. — Donald J. Trump (@realDonaldTrump) May 8, 2017 
 
 Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Council. — Donald J. Trump (@realDonaldTrump) May 8, 2017 
 
 "General Flynn was given the highest security clearance by the Obama administration -- but the Fake News seldom likes talking about that," Trump said in his first missive. 
 
 "Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Counsel," he tweeted. 
 
 Flynn began advising Trump on national security in early 2016 and soon became a constant presence by Trump's side as he crisscrossed the country from rally to rally. 
 
 He frequently introduced Trump on the campaign trail, delivering introductory remarks rife with criticism of the Obama administration's foreign policy and of Democratic nominee Hillary Clinton. Flynn often led Trump supporters in chants of "Lock her up!" as he accused her of corruption and negligence in her use of a private email server. 
 
 Trump came to value Flynn not only for his like-minded view of global affairs but for his loyalty throughout the campaign. 
 
 CNN's Jake Tapper, Kevin Liptak, Pamela Brown and Gloria Borger contributed to this report. ||||| Breaking News Emails Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings. 
 
 May 8, 2017, 3:10 PM GMT / Updated May 8, 2017, 3:33 PM GMT By Kristen Welker, Dafna Linzer and Ken Dilanian 
 
 Former President Obama warned President Donald Trump against hiring Mike Flynn as his national security adviser, three former Obama administration officials tell NBC News. 
 
 The warning, which has not been previously reported, came less than 48 hours after the November election when the two sat down for a 90-minute conversation in the Oval Office. 
 
 A senior Trump administration official acknowledged Monday that Obama raised the issue of Flynn, saying the former president made clear he was "not a fan of Michael Flynn." Another official said Obama’s remark seemed like it was made in jest. 
 
 According to all three former officials, Obama warned Trump against hiring Flynn. The Obama administration fired Flynn in 2014 from his position as head of the Defense Intelligence Agency, largely because of mismanagement and temperament issues. 
 
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 Obama’s warning pre-dated the concerns inside the government about Flynn’s contacts with the Russian ambassador, one of the officials said. Obama passed along a general caution that he believed Flynn was not suitable for such a high level post, the official added. 
 
 Two administration officials said Obama also warned Trump to stay vigilant on North Korea. 
 
 The revelations came on the same day that former acting Attorney General Sally Yates testified about the events that led to Flynn's eventual firing. Separately, two U.S. officials told NBC News that the Defense Intelligence Agency didn't know Flynn had been paid nearly $34,000 by a Russian state media outlet when it renewed his security clearance in April 2016. 
 
 Trump named Flynn as his national security adviser. Flynn, who was conducting private conversations with the Russian ambassador regarding sanctions, was then fired three weeks into the administration for misleading Vice President Pence about those conversations. 
 
 Obama and Trump shake hands following their meeting in the Oval Office on Nov. 10, 2016. Pablo Martinez Monsivais / AP 
 
 News of the Obama warning came as Trump sought to get ahead of a day of unpleasant disclosures about his former top foreign policy aide, taking to Twitter Monday to cast aspersions on Yates, the 27-year Justice Department prosecutor who warned the White House that then-National Security Adviser Mike Flynn had misled officials about his conversations with the Russian ambassador. 
 
 Related: White House Denies Claim That Yates' Testimony Was Blocked 
 
 "Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Counsel," Trump tweeted, referring to Yates’ conversation with White House counsel Donald McGahn. 
 
 But Trump has left many other important questions about the Flynn affair unanswered, including: What, if anything, did he know about his national security adviser’s conversations with the Russian ambassador? 
 
 Monday afternoon, Yates is scheduled to testify for the first time in public, alongside James Clapper, the former director of national intelligence, who pushed Flynn in 2014 from his job as director of the Defense Intelligence Agency. The two are due to appear before a Senate Judiciary subcommittee at 2:30 p.m. 
 
 It was more than a week after Yates raised concerns about Flynn with McGahn that the story leaked to the Washington Post, prompting a series of events that led to Flynn’s ouster from his White House job. 
 
 In a second tweet Monday morning, Trump noted that "General Flynn was given the highest security clearance by the Obama administration, but the Fake News seldom likes talking about that." 
 
 It’s true that Flynn got his top level security clearance renewed in January 2016, but what Trump didn’t mention is that Flynn should have received a far more thorough vetting in advance of his becoming national security adviser, a job that allows access to the nation’s most closely-held secrets. What was the nature of that vetting, and did it raise any flags about Flynn’s lobbying work for Turkish interests during the campaign, or his paid appearance on behalf of Russian state media, both now under scrutiny by law enforcement agencies? The White House hasn’t said. 
 
 Related: Flynn Never Told DIA That Russians Paid Him, Say Officials 
 
 Another big question that has never been answered: Did Flynn coordinate with the president over his repeated contacts with Russian ambassador Sergey Kislyak? Those contacts raised alarms not only within the Obama administration, but within Trump’s own transition team, according to reports Friday confirmed by NBC News. There were concerns that the Trump administration was signaling Russia not to worry about the Obama administration sanctions on Russia over its election interference, which expelled Russian intelligence officers from the U.S. and blocked access to Russian diplomatic compounds here. 
 
 Flynn was fired as national security adviser, White House officials said, because he told Vice President Pence he didn’t discuss those sanctions with Kislyak, despite FBI transcripts showing that he did. That is among the issues Yates raised to McGahn, according to people who have been briefed on the matter. 
 
 People familiar with her plans don’t expect her to get into much detail about her warnings regarding Flynn, largely because many of the underlying facts involve classified material. 
 
 In advance of her testimony, Republicans have been accusing her of acting politically, and noting that she was fired by Trump for refusing to enforce his travel ban. They call her a partisan Democrat. 
 
 Related: Former Acting AG Sally Yates to Testify Publicly in House Intel Probe 
 
 In response, her defenders point out that she spent much of her 27-year Justice Department career working as a line prosecutor, a non-political job. Though she was appointed to positions in both the Clinton and Obama administrations, she was widely respected on both sides of the aisle. Georgia Republican Johnny Isakson, her home state senator, was among those introducing her at her 2015 confirmation hearing to become deputy attorney general. 
 
 She was confirmed, 84-12.
– When then-President Obama met with President-elect Trump in the Oval Office two days after the election, NBC News reports that Obama gave him a specific piece of advice: Don't hire Michael Flynn. (CNN says it has confirmed the story.) Trump did not take the advice and went on to make Flynn his national security adviser, only to fire him three weeks later when it emerged that Flynn had misled the White House about his conversations with the Russian ambassador. Obama's concerns, however, were more about Flynn's temperament, reports NBC, which notes that the Obama administration fired Flynn in 2014 from his post as head of the Defense Intelligence Agency. Obama reportedly told Trump that Flynn was not suited to such an important position. The revelation comes on the day that Sally Yates, who served briefly as acting attorney general between the two administrations, is expected to testify before Congress about her concerns over Flynn's contact with Russian ambassador Sergey Kislyak. Trump himself addressed both aspects of the story on Monday: "General Flynn was given the highest security clearance by the Obama Administration - but the Fake News seldom likes talking about that," he tweeted. (Spokesman Sean Spicer previously blamed the Obama White House, citing Flynn's clearance to run the DIA.) And on Yates, Trump tweeted: "Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Counsel."