LOS ANGELES — The FAA is conducting an investigation following the return of a Sun Country Airlines Boeing 737 to Los Angeles International Airport. The aircraft had flames visible from its right engine on Monday.

“We were barely airborne for 25 minutes when it sounded as if lightning struck the aircraft or something had exploded,” passenger Ruth Sorensen shared with CNN. “We could hear the engine powering down after the incident, and then saw flames coming out.”

Flight 430, headed to Minneapolis/St. Paul International Airport with 166 passengers, encountered “an issue” with one of its engines shortly after takeoff, prompting it to declare an emergency, according to a statement from the airline.

“I was actually seated next to the engine that caught on fire. I saw just a really bright flash out the window,” A passenger named Sarah told CNN affiliate WCCO. “The passenger next to me held hands and kind of comforted each other, bracing for the worst.”

The pilots declared an emergency and returned to land safely at LAX where they were met by fire trucks before eventually taxing to the gate.

“We slept on the airport floor from 3 a.m. until 8:30 a.m. to get on a new Sun Country flight to go home,” Sorensen said.

“Our passengers and crew are our priority, and we appreciate the professionalism of our pilots and flight attendants to ensure the safety of our customers,” the airline said in a statement.

CNN’s Christine Sever contributed to this report.