A plane was forced to make an emergency landing when a piece of the wing "fell off" mid-flight.

One passenger on the Southwest Airlines flight from from Austin to Harlingen in Texas, U.S. took a photo of the wing from his seat that the airline have said was at "an irregular angle."

The Boeing 737 made a safe landing at San Antonio Airport and the 109 people on board were disembarked safely.

Lorenzo Hernadez Jnr took to Facebook to speak of what he described as his "near death experience."

"During the flight on the left side of the plane, fasteners came or broke off the wing," he wrote on the social networking site.

"I heard a few people to the side of me scream to the aircrew, a piece broke and flew off and a panel was hanging."

He goes on to describe how people were "praying" as the plane experienced "the worst turbulence ever."

"I am glad to say the great staff and pilots kept calm and stabilized the plane after a few minutes," he added.

A spokesperson for Southwest told MailOnline Travel: "The captain of Flight 987 scheduled from Austin to Harlingen made the decision to divert to San Antonio due to a flap track canoe fairing appearing to be at an irregular angle."

"The flight carrying 109 passengers and five crew landed safely without incident in San Antonio at 4:32 p.m. CT. There were no injuries and the aircraft was safely towed to a gate. "

"We are removing the aircraft from service for further inspection."

Another passenger on the flight, Hayden Ellis, told Channel 5 News how the pilot came onto the tannoy and told passengers that something "fell off" the wing.

"I think even the pilots were kind of uncertain as to what had happened but the pilot came on and said, uh, yup, everyone remain calm, a piece of the plane...or he said a piece of the wing fell off," said Mr Ellis.

Clarissa Ellis added: "Someone had called a flight attendant because they noticed something wrong with the wing and at that point the flight attendant did come on"and she said: "We are fully aware of the situation."