UPDATE: Fire Reported at Atlanta GYN-OB on Pleasant Hill Road

Update 10 p.m. Sunday, May 20

Fire investigators are calling a Sunday morning fire at a Lilburn gynecology/obstetrics office "suspicious," according to a Gwinnett Fire spokesman.

A fire at  around 4:20 a.m. Sunday caused extensive interior damage to the business, which is located in a multi-use commercial office building in the 400 block of Pleasant Hill Road, near Berkmar High School.

No one was in the building when fire personnel arrived and no injuries were reported.

Gwinnett Fire Capt. Tommy Rutledge said in a media release Sunday night that the incident is under active investigation.

"Gwinnett Fire Investigators are not releasing specific information about the fire, but have called the circumstances suspicious in nature," Rutledge said in an emailed update. "The fire has not yet been ruled arson, but is simply listed as undetermined under investigation."

Firefighters responded to a call from an alarm monitoring company about the fire at the building, which houses medical offices and an insurance company.

Firefighters found a heavily involved fire on arrival. It took about an hour to get the fire under control.

Check back with Lilburn Patch for updates.