(CNN) -- A computer problem has caused a disruption with the departure of United Airlines planes Friday night, the airline said.
The Chicago-based airline said a computer outage at 7:15 p.m. CT interrupted United Airlines' systems of scheduled departures, reservations and processing systems.
"Our technology team is working to resolve the issue as soon as possible. We apologize for the disruption being caused to travelers at affected airports and we are seeking to resume operations as quickly as possible," a company spokesman said.
Karen Pride of the Chicago Department of Aviation told CNN the agency is providing extra security personnel and terminal management staff to assist United with the situation at O'Hare International Airport.
Michael Goldenthal, who was on an airplane at O'Hare when the problem occurred, said it became apparent something was wrong as the flight was taxiing.
"We were on the runway when the pilot came on the P.A. and said they had lost contact with the company computer system which measured the weight of the plane. "
Goldenthal said the aircraft taxied around for nearly an hour and then returned to the gate for additional fuel. But passengers were not allowed to get off.
The flight crew told passengers, Goldenthal said, that "the computer system was down not only in Chicago but across the system."
CNN's Greg Morrison contributed to this report