The FBI is leading an investigation Thursday into an explosion at a post office in northwestern Indiana that injured a postal worker.

The (Northwest Indiana) Times reports that FBI Special Agent Bob Ramsey said the woman was taken to a hospital after the explosion about 6 p.m. on Wednesday in East Chicago. Details of her injuries weren’t released, but Fire Chief Anthony Serna said they weren’t life-threatening.

An FBI statement to the Chicago Sun-Times said it’s “yet to be determined if this is an act of domestic or international terrorism, but at this time there is no ongoing public safety concern.” The statement said the investigation was in its early stages.

The Associated Press left a message with the FBI Thursday seeking new information.

In addition to federal agents and local fire officials, local law enforcement also assisted in the investigation. The Porter County’s bomb squad responded with a bomb disposal robot. K-9 units from the Lake County Sheriff’s Department were at the scene.

A roadway near the post office was blocked off as authorities investigated.

(AP)