WASHINGTON, Jan. 11 (Xinhua) -- The U.S. Federal Aviation Administration (FAA) said on Wednesday that it had traced the system outage that temporarily grounded all domestic flights earlier in the day to "a damaged database file."

The FAA, which regulates all aspects of civil aviation in the United States, announced preliminary work to determine the root cause of the system outage.

"At this time, there is no evidence of a cyber attack," the U.S. aviation regulator wrote in an update on Wednesday evening.

The FAA ordered airlines to pause all domestic departures Wednesday morning to allow the federal agency to validate the integrity of flight and safety information before lifting the ground stop hours later.

The incident, which led to thousands of delayed and canceled flights within, into, or out of the United States on Wednesday, followed an overnight outage to the system that provides safety info to flight crews.