US grounded planes as a 'precaution' after a North Korean missile launch

An unusual ground stop was issued to some pilots for a short period of time following a North American Aerospace Defense Command alert of a launch of a North Korean missile, a US official said Tuesday.

The official says it was not a national ground stop and may have been issued by a regional air traffic control facility.

"No warning was issued by NORAD HQ," regarding a potential threat to the US, according to Captain Pamela Kunze, the chief NORAD spokesperson.

NORAD has not responded to CNN's multiple requests for comment...