White House press secretary Sean Spicer on Thursday downplayed the ongoing scandal involving former national security adviser Mike Flynn by saying Flynn's security clearance was approved in 2016 by the Obama administration, and that the incoming Trump administration accepted his clearance and others that were approved by Trump's predecessor.

"Gen. Flynn was a career military officer who maintained a high-level security clearance throughout his career in the military," Spicer said in the press briefing. "His clearance was last re-issued by the Obama administration in 2016 with full knowledge of his activities that occurred in 2015."

"So the issue is, you know, he was issued a security clearance under the Obama administration in the spring of 2016," he said.

Flynn has been under fire over whether he reported payments from the Russia Today television station for a 2015 trip, as he had been required to do as a retired Army general.

"The trip and transactions that you're referring to occurred in December of 2015, from what I understand," Spicer said.

Flynn resigned as national security adviser in February, following reports he misled the administration, including Vice President Mike Pence, about his contacts with Russian ambassador Sergey Kislyak during the transition. These conversations would have happened after the Obama administration's issued his security clearance.

Still, Spicer stressed that Flynn's last clearance by the Obama administration took into account his trip to Russia and related payments.

"All of that clearance was made during the Obama administration and apparently with knowledge of the trip that he took," Spicer said. "That's how the process works and I welcome the Department of Defense's review." It was revealed Thursday that the Inspector General for the Department of Defense is launching a probe into whether Flynn accepted payments from foreign sources.

Spicer said the Trump transition team relied on the background check the Obama administration did for Flynn when he took over as the director of the Defense Intelligence Agency, and the checks done of many other officials.

"Every individual came into this White House either applied for a security clearance or had one," Spicer said. "Everyone in the government goes through the same SF 86 process. Every single person. And so 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? That's it."