"I think the number (of deaths) could go up. We have at least 11 injured people, some of them very seriously, who are being treated in hospitals," Beshear said during a press conference.
The plane belongs to the package distribution company UPS and is believed to have crashed shortly after takeoff, according to the US aviation authority FAA, which is investigating the incident together with the aviation safety authority NTSB.
Footage from the scene shows a fire spreading on the ground as a thick column of smoke rises into the sky. The public is urged to stay indoors.
"This is a serious situation. Please pray for the affected families," Beshear wrote on X earlier.
The crash occurred at 5:15 p.m. local time. The plane was en route to Honolulu, Hawaii.
All flights to and from Louisville Airport, UPS's global hub, have been temporarily suspended.
