PHILADELPHIA (WPVI) --A fire was reported onboard a Philadelphia-bound American Airlines flight, but was quickly extinguished.
No injuries were reported from the incident Wednesday just before 9 a.m. at the Seattle-Tacoma International Airport to Philadelphia
American Airlines flight 728 was set to leave for Philadelphia when the fire broke out.
In a statement to Action News, American Airlines says "Prior to departure from Seattle, American Airlines flight 728 experienced a mechanical issue with the auxiliary power unit (APU). The Port of Seattle Fire Department responded after flames were reported from the APU exhaust."
After the fire was extinguished, the plane headed back to the gate.
"We apologize to our passengers for the inconvenience," American Airlines said.
There were no injuries to the 151 passengers and six crewmembers.
The plane departed Seattle around 2 p.m. ET.
The Associated Press contributed to this report.