New York: Hundreds of flights were grounded across the United States after a computer outage at the Federal Aviation Administration (FAA), US media reports said on Wednesday.

The outage comes as a result of the failure of the FAA's NOTAM (Notice to Air Missions) system, which alerts pilots and other personnel about airborne issues and other delays at airports across the country," Fox News reported.

The FAA said it is working to restore its Notice to Air Missions System.

"We are performing final validation checks and reloading the system now," it said, adding that operations across the National Airspace System are affected.

"We will provide frequent updates as we make progress," it said in a tweet.

While the FAA has not enforced a grounding of aircraft due to the outage, most airlines have chosen to ground their own plane due to the system's failure. The failure has so far resulted in some 400 cancelled flights across the US, Fox News reported.