One of President Donald Trump's nominees for a top Pentagon job said Tuesday it is "insane" civilians can buy assault rifles – a starkly different position from the administration's pro-gun stance.

"I'd also like to, and I may get in trouble with other members of the committee, just say how insane it is that in the United States of America a civilian can go out and buy a semiautomatic assault rifle like an AR-15," Dr. Dean Winslow, the nominee for the Department of Defense's top health affairs job, said during his confirmation hearing in front of the Senate Armed Services Committee, Vox reported.

The AR-15 is the semi-automatic counterpart of the U.S. military's M-16 rifle and the nation's No. 1 selling gun, according to Mediaite, which flagged the testimony.

Winslow also mentioned the Air Force's failure to alert federal authorities Delvin Kelley was convicted of a crime, which might have kept him from buying the military-style rifle he used in the massacre of 26 churchgoers Sunday.

But Sen. John McCain, R-Ariz., chairman of the Senate Armed Services Committee, was irritated by Winslow's assessment, saying "I don’t think that's in your area of responsibility or expertise," Vox reported.

Video of Winslow's testimony was posted by the Senate committee.