White House press secretary Sean Spicer on Monday highlighted FBI Director James Comey's testimony on the "unmasking" of Gen. Mike Flynn, the former national security adviser who was dismissed in February after leaks about his pre-inaugural conversations with the Russian ambassador.

"Director Comey told the House Intelligence Committee that certain political appointees in the Obama administration had access to the names of unmasked U.S. citizens," Spicer said.

"Before President Obama left office, Michael Flynn was unmasked and then his identity was illegally leaked" to the media, Spicer said.

Flynn's conversation with the Russian ambassador was collected by intelligence officials surveilling the Russian diplomat. The redaction of Flynn's identity was removed by whoever leaked the details of his phone call with Ambassador Sergey Kislyak.