A Southwest Airlines flight was diverted Wednesday after a passenger died on the plane en route to Phoenix.

Flight 1274 left the St. Louis airport just after 1 p.m. Arizona time when 71-year-old David Dougherty died in flight, officials said.

The plane was diverted to the Tulsa International Airport.

Authorities at TIA say they responded to an alert call regarding cardiac arrest.

Tulsa police also responded to the scene.

Southwest Airlines spokeswoman Olga Romero says there were medical personnel on board the flight who coordinated with crews on the ground to treat him. But authorities say the passenger was pronounced dead upon arriving at the airport.

Police Sgt. Tim Lewandowski said Dougherty had a terminal illness.

Officers said Dougherty was traveling with a family member.

The remaining passengers boarded, again, in Tulsa and flew to Phoenix.

The flight was expected to arrive in Phoenix at 6:18 p.m.