A United Airlines flight was forced to make an emergency landing after one of its engines caught fire midflight.

The plane, which was flying from San Diego to Chicago, was diverted to Albuquerque after flames were seen coming out of one of the engines on the right wing early Monday morning.

One passenger who witnessed the blazed filmed the incident on his phone.

"Strange to sit there & think ‘What if this is it?’ To just sit there & accept the potential fate that seems to be a possibility & not tell the sleeping people all around you. No need to panic the others. I’m a pretty calm person but took me a while to stop the shakes & trembles," the passenger, Thomas Chorny, wrote on Twitter.

Most of the passengers were asleep when the incident occurred. The crew shut off the affected engine to extinguish the flames.

No injuries were reported. The cause of the engine fire is currently unknown.