HOMERVILLE, Ga. -- An explosion and fire destroyed a coffee shop Friday in this rural south Georgia city, injuring three workers and prompting a warning from city officials for residents to avoid the downtown area.

The blast rocked tiny Homerville, a city of about 2,500 people, shortly after noon. Investigators did not suspect foul play and were looking into whether it might have been an accidental gas explosion, said Glenn Allen, spokesman for Georgia Insurance and Safety Fire Commissioner Ralph Hudgens.

"We are looking potentially at natural gas as a cause because there was a construction crew in the area digging at the time of the explosion," Allen said. "But right now the exact cause is unknown."

Allen said the explosion and a resulting fire destroyed the small, single-story building that housed Coffee Corner. A photograph taken by an investigator at the scene showed the building's roof had partially collapsed. Brick walls were blasted apart, with bricks scattered in the parking lot and piled atop two cars parked beside the shop.

Three employees were the only people inside the coffee shop when it exploded, Allen said. It wasn't immediately known how seriously they were injured, he said, but all three workers were airlifted to a hospital in Gainesville, Florida.

Homerville is located roughly 30 miles (48 kilometres) from the Georgia-Florida line. Officials used the city's Facebook page to urge residents Friday to stay away, referring only to "issues within the downtown area."

"First responders and all other crews need the area to be as free of traffic as possible in order to get their jobs done," the city's Facebook post said.

Nan Mikell, Homerville's city manager, did not immediately return phone and email messages. No one answered the phone at the Clinch County Emergency Management Agency. The phone number for Homerville police was forwarded to Mikell's voicemail.