By Keith Allen and Steve Almasy CNN

(CNN) -- A manhunt was underway at Will Rogers World Airport in Oklahoma City after a Southwest Airlines employee was fatally shot Tuesday in the parking lot.

The airline said, "The Southwest Airlines Family is deeply saddened by the passing of our Southwest Family Member, and we extend our heartfelt sympathies and support to his family and Southwest coworkers at this time."

The victim is Michael Winchester, the Oklahoma City Police Department tweeted on its verified account. He was believed to be 51.

The airport has been closed to commercial traffic since the shooting, though one government plane landed.

Police advised anyone inside the facility to "shelter in place," a tweet from the department said. Police said they were moving people from inside the airport to a nearby road.

Shots were fired in a parking lot, Capt. Paco Balderrama told reporters.

"We located one victim and we're looking for a second reported victim," he said. "We don't have any information to put out on the suspect vehicle or the suspect itself, but gunshots were heard."

Five airlines fly out of Will Rogers to 21 destinations. The airport sees 150 commercial flights a day and more than 3.6 million passengers each year, the city's website says.

Southwest Airlines said it was canceling the remainder of its flights scheduled to depart Tuesday.

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