United flight lands in San Diego after device aboard catches fire

A flight had to return to San Diego International Airport Tuesday after a device caught on fire onboard.  

The San Diego Fire Department said an external battery pack caught on fire in the cabin, but the flight crew stopped it from spreading by placing a fire bag over it. 

Authorities said all passengers and crew members were medically evaluated. Four people were taken to UCSD Hillcrest.

"This morning, United Airlines flight 2664 departed San Diego International Airport heading to Newark," an airline spokesperson told FOX Television Stations. "Shortly after departure, the aircraft declared an Alert 2 which indicates a major difficulty with the aircraft, in this case there was an electrical device fire in the cabin."

"The aircraft landed safely at San Diego International Airport where emergency crews responded to the aircraft and assisted passengers. No other operations were impacted," the statement continued. 

"SDFD crews at SD Intl Airport for a plane that came in w/ an external battery pack on fire in the cabin," the San Diego Fire Department tweeted. "Flight crew prevented the fire from spreading to the cabin. Two patients transported to hospital and more being eval'd."

FOX Television Stations has reached out to United Airlines for comment. 

According to the Federal Aviation Administration, spare (uninstalled) lithium ion and lithium metal batteries cannot be placed in checked luggage and must be placed in carry-on baggage.  

This story is developing. Check back for updates.