Former U.S. President Barack Obama warned then-President-elect Donald Trump not to give the post of national security adviser in his administration to Michael Flynn, who was eventually fired in a controversy about ties to Russia, a former Obama aide said.

Obama gave the warning in a one-hour Oval Office meeting with Trump two days after the Republican's surprise Nov. 8 election win. The warning, first reported by NBC News, came up during a discussion of White House personnel.

White House spokesman Sean Spicer, responding to the reports, told a news briefing: "It's true that the president, President Obama, made it known that he wasn't exactly a fan of Gen. Flynn's, which frankly shouldn't come as a surprise to anyone, given that Gen. Flynn had worked for President Obama, was an outspoken critic of President Obama's shortcomings, specifically as it related to his lack of strategy confronting ISIS and other threats."