(BUSINESS INSIDER) — A Southwest Airlines flight made an emergency landing in Dallas on Saturday evening after the cabin started to lose pressure, the airline has confirmed to Business Insider.

Southwest Flight 861 was traveling from Denver to Dallas when the oxygen masks deployed and passengers were asked to put them on. An airline representative told Business Insider there were 120 passengers on the flight, four of whom asked medical personnel to evaluate ear pain after landing.

“The crew of Flight 861 traveling from Denver to Dallas Saturday night radioed ahead for paramedics to meet the aircraft after a pressurization issue in flight,” the representative said. “Following an uneventful landing, initial reports indicate four of the 120 customers onboard requested a check from paramedics to assess ear pain. All of the customers were ending their journey with us in Dallas, as was the aircraft, which underwent a maintenance review.”

Note: Read our discussion guidelines before commenting.