New Delhi, Aug. 7 -- United Airlines grounded flights on key routes across United States on Wednesday due to a technology issue, with the airline warning that further delays could continue into the evening.

According to an alert from the Federal Aviation Administration (FAA), all United Airlines flights headed to Chicago were temporarily grounded at their departure airports. The disruption also affected flights departing from major hubs including Denver, Newark, Houston, and San Francisco.

"Safety is our top priority, and we'll work with our customers to get them to their destinations," an emailed statement from the Chicago-based airline said without disclosing the specifics of the problem, AP reported.

An AP journalist had boarded a U...