New Delhi, Feb. 2 -- Flights across the United States are likely to experience 'residual delays' on Sunday morning due to an outage from the previous evening in the primary NOTAM system, according to US transportation secretary Sean Duffy.

The Federal Aviation Authority (FAA) is working to restore the temporary outage, Duffy said.

"The primary NOTAM system is experiencing a temporary outage, but there is currently no impact to the National Airspace System because a backup system is in place," he wrote on X.

"All active NOTAMs were available until the time of the outage. The agency activated its contingency system to supplement and support preflight briefings and continue flight operations. We are investigating the root cause and we wil...