Barack Obama warned Trump against hiring Michael Flynn

In November, then-President Barack Obama warned President-elect Donald Trump against hiring retired Lt Gen Michael Flynn as his national security adviser, former Obama administration officials said on Monday.

Obama warned Trump about Flynn during their Oval Office meeting on November 10, days after Trump was elected president, the officials told CNN.

Obama's concerns, which he relayed to Trump, 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, CNN added.

The White House confirmed later on 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 was not exactly a fan of Gen Flynn's," press secretary Sean Spicer was quoted as saying.

He said the concerns should not 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.