UPDATE 2- All flights in US temporarily grounded amid computer system failure

CHANGES HEADLINE, DECK, LEDE, CHANGES THROUGHOUT

By Dilara Hamit and Zehra Nur Duz

ANKARA (AA) - After flights were temporarily grounded in the US on Wednesday when the air travel authority reported a computer system outage, the country's transportation secretary said there was no evidence of a cyberattack behind the problem.

President Joe Biden was briefed on the Federal Aviation Administration (FAA) outage by Transportation Secretary Pete Buttigieg, and Biden directed the Department of Transportation to investigate the outage, said the White House press secretary.

"There is no evidence of a cyberattack at this point, but the President directed DOT to conduct a full investigation into the causes. The FAA will provide regular updates," Karine Jean-Pierre said on Twitter.

"Operations across the National Airspace System are affected," the FAA said on Twitter, noting that it was working to restore its Notice to Air Missions System.

"We are performing final validation checks and reloading the system now," it added.

The FAA provides air traffic services to over 45,000 flights daily carrying 2.9 million passengers in the National Airspace System, according to its website.

The system is an airspace network that includes air navigation facilities, airports, and landing areas.

The FAA had also ordered airlines to halt all domestic departures until 9:00 a.m. eastern time (1400GMT) to enable the agency to "validate the integrity of flight and safety information," it said in a separate Twitter post.