Southwest Airlines Co. said Wednesday it will enter the Minneapolis-St. Paul market in March, its first new city in more than 11/2 years.

The move will put the Dallas-based carrier in direct competition with Northwest Airlines Inc., which operates a major connecting hub there.

Chairman and chief executive Gary Kelly said Southwest will start with nonstop flights from Minneapolis-St. Paul to Chicago's Midway Airport.

The expansion comes as Southwest has mostly throttled back its growth. But Mr. Kelly said the carrier is still looking for the right places to grow.

"In this environment where capacity is being reduced by our competitors and fares are going up, there are tremendous opportunities for Southwest Airlines to expand," he said.

Mr. Kelly said the decision to enter Minneapolis was not prompted by either the pending Northwest-Delta Air Lines Inc. merger or the financial problems that Minneapolis-based Sun Country Airlines Inc. is having.