Law enforcement and fire officials were investigating a potential threat on a plane at Denver International Airport, but police later said the threat was unfounded.

Passengers slid down an emergency slide of a smoking jet at Denver International Airport due to a possible problem with the plane’s landing gear, authorities said.

The combination of blown tires and the deceleration of the plane during braking resulted in a brake fire that was extinguished by the Denver Fire Department, according to American Airlines.