One of the world's largest commercial airlines is for the first time providing passenger service to and from Rochester, Minn.

United Airlines announced Monday morning that it will operate flights between Rochester and O'Hare International Airport in Chicago, home to the passenger carrier's headquarters.

Three flights in each direction begin June 8, United said Monday.

Rochester International Airport already has daily service from major carriers Delta and American.

"The addition of this service will provide 150 new departing seats per day, which is a capacity increase of 35 percent for our community," said John Reed, the airport's executive director.

United's outbound flights on 50-seat regional jets will leave at 5:35 a.m., 11:30 a.m. and 2:03 p.m. Inbound flights from Chicago have departures set at 9:20 a.m., 12:15 p.m. and 7:30 p.m.

As an example, a June 8 flight to Chicago and returning June 12 booked on united.com shows a round-trip economy fare of $310.

The addition of Rochester by United is part of a substantial expansion of domestic and European service that it announced Monday.

Rochester's airport was established in 1928 by the Mayo Clinic, which relies heavily on air service for its personnel and patients.

It is owned by the city and operated by Rochester Airport Co., a Mayo subsidiary.

"Transportation to Rochester has emerged as a major theme in our destination planning for our patients and the community," John T. Wald, medical director of marketing for Mayo Clinic.

"This exciting announcement opens the door to additional one-stop connections making travel to Rochester more convenient for our patients and visitors."

United spokeswoman Maddie King said, "This new route provides patients and their families from around the world with better access to Rochester's renowned medical community with nonstop or one-stop service."

United, which serves 360 cities on five continents, is joining rivals American and Delta in Rochester.

American connects Rochester and Chicago O'Hare, while Delta connects Rochester with Atlanta and Minneapolis. Combined, the three will offer 11 daily departures.

Last fall, members of Minnesota's congressional delegation announced a $7.3 million U.S. Department of Transportation grant for improving the Rochester airport's customs facility.

The new 20,000-square-foot project in the main terminal will provide for a passenger boarding bridge, a concourse holding room, a baggage claim, improvements to security screening and a better operation to process business and VIP flights.

The Department of Homeland Security had issued an unfunded mandate to replace the existing facility at an anticipated cost of $12 million.

Without the improvements, customs would have moved from the airport and its "international" designation would have been pulled.