Hanwha Aerospace's Daejeon R&D Campus / Courtesy of Hanwha Aerospace

DAEJEON — An explosion was reported at Hanwha Aerospace's facility in the central city of Daejeon on Monday, with firefighters working to put out a blaze, officials said.

Authorities received the report of the explosion at the defense company's facility in the city, some 140 kilometers south of Seoul, at 10:59 a.m., according to the officials.

It was not immediately clear if anyone has been injured in the incident.

Police and fire officials believe the suspected explosion may have been caused by propellant used in propulsion systems and plan to investigate the exact cause of the incident.