FAA lifts brief nationwide ground stop for United Airlines

A brief nationwide ground stop for United Airlines flights was lifted Tuesday, the Federal Aviation Administration said.

"Earlier today a software update caused a widespread slowdown in United's technology systems," United said in a statement.

"We briefly held aircraft at their origin airports and resumed normal operations around 12:45 p.m. CT.," the airline said. "Our teams are working to get customers to their destinations as soon as possible."

The ground stop lasted slightly more than an hour and did not affect aircraft already in flight when it was called. United is investigating the cause of the slowdown but does not believe it is a cybersecurity issue.

United's stock price closed more than 2% lower Tuesday.