Following panic over an internal memo, the Office of the National Security Adviser (ONSA) has assured there is no threat to the nation’s airports in any form.   It said it only sent an advisory to security agencies to liaise with airport management to upgrade existing security measures at the nation’s airports.   ONSA described the advisory as a “routine threat assessment” to ensure the preparedness of all relevant agencies.   The clarifications were made in a statement by the Head of Strategic Communication in the Office of the National Security Adviser (ONSA), Mr. Z.M. Usman.