United Airlines flights on major routes were grounded Wednesday because of a technology issue, and additional flight delays were expected into the evening, the airline said.

There is a ground stop for Untied Airlines flights at Chicago O'Hare Airport Wednesday evening. United said in a statement that a "technology issue" is causing them to hold departures.

A ground stop is currently in effect for all United Airlines flights heading to Chicago and other major airports across the country because of a "technology issue."