At least one employee suffered minor injuries Wednesday when "one, possibly two explosive devices detonated" in a post office in East Chicago, Indiana, according to an ATF spokesperson.

The fire department received the call of a possible explosion at the East Chicago Main Passport Post Office around 6 p.m. at 901 E. Chicago Ave., acting East Chicago Fire Department Chief Francisco Mendez said.

“Right now the FBI, ATF, all the agencies are here, we’re investigating,” Mendez said. “I can confirm there was at least one detonation.”

He said he could not confirm if there were any other explosions but bomb technicians were preparing to sweep the post office for more explosive devices.

“I cannot tell you exactly where, but it was inside and we believe it was a package,” Mendez said, adding that he could not confirm what kind of device or devices were found. The Times of Northwest Indiana reported a fire official confirmed there were two pipe bombs found in the building.

There were two people, including the injured employee, inside the building when the explosion occurred, Mendez said. A third person was outside of the building "making deliveries." He added that he believed the post office was closed for the day during the explosion.

The FBI in Indianapolis said was leading the ongoing investigation into the explosion.

"At this early stage in the investigation it has 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 FBI said in a statement.



Part of Chicago Avenue was closed to traffic as emergency response vehicles with red and blue flashing lights formed a perimeter around the facility.

Calls to the East Chicago Police Department went unanswered.