A Southwest flight from Denver is making an emergency landing after a “mechanical issue,” the airline said.

A Southwest Airlines plane was forced to make an emergency landing Sunday morning after the engine cover came off during takeoff, according to the Federal Aviation Administration.

The plane, a Boeing 737-800, which was scheduled to fly from Denver to Houston, landed safely at Denver International Airport just after 8 a.m. and was towed to the gate, according to the airport and the airline.

According to the Federal Aviation Administration, which is now investigating the incident, crew members on board said: “The engine cover fell off during takeoff and hit the wing flap.”

Southwest Airlines said in a statement that the flight “landed safely after experiencing a mechanical problem.” The airline said customers have been rebooked on other flights, and maintenance teams are now examining the plane.

Footage taken by some passengers showed what appeared to be part of the plane dangling and flapping in the breeze.

“It's all blown up,” one person can be heard saying in a video taken by passenger Lisa See, after which several people on board can be heard cheering as the plane lands.

Lisa See told ABC News that the engine cowl “peeled off within the first 10 minutes” of the flight.

“We were all kind of in shock, and I looked out the window because I love window seats, and there he was,” she said.

Another passenger, Cooper Glass, told ABC News the experience was “scary.”

“People in the checkout line across from me started yelling at the flight attendants and showing them the damage,” Glass said.

Glass praised the pilot and said he “did a great job landing.”

ABC News' Sam Sweeney, Samira Said and Helena Skinner contributed to this report.