United Airlines said on July 2 that a computer outage that had caused flight delays with its operations at Chicago's O'Hare International Airport was being resolved, but advised travelers to continue to check the status of flights on its Website.

"United's check-in systems have been addressed and the number of flights arriving and departing O'Hare is improving," United spokeswoman Jean Medina said in a statement.

"While we continue to expect some delays, we expect to resume scheduled operations this afternoon," she added.

Earlier on July 2, local media had reported that long lines of passengers were stretched from inside United's terminal to the sidewalk outside O'Hare after a computer problem resulted in flight delays and some cancellations ahead of the busy July Fourth holiday.

The carrier, a unit of UAL Corp, said customers could take advantage of United's travel waiver, which would allow changes without some penalties, if they wanted to change their travel plans.

"We apologize to our customers for the inconvenience this morning and recommend they continue to use www.united.com to check flight status and check-in," Medina added.