McDonald's plans to expand its relationship with Uber Technologies as it seeks to offer delivery of its food to customers in more U.S. cities.

The Oak Brook-based burger chain, which has been testing delivery through the UberEats mobile app in about 200 restaurants in Florida since December, said today it will launch delivery in several cities by the end of June.

"We're encouraged about the start we've had," CEO Steve Easterbrook said on a conference call with analysts and investors. "We are not in test mode, we are expanding."