SEOUL, South Korea — An explosion and fire occurred at a defense company in South Korea on Monday, killing five people and injuring two others, officials said.

The deadly incident happened at a worksite run by Hanwha Aerospace in the South Korean city of Daejeon.

Other details, including the cause of the explosion, were not immediately available.

Emergency official Yoon Seong-su said that the area is a government-designated security facility.

Local medical official Kim Ju-yeon said one of the two injured people was in a critical condition. She said authorities haven’t yet identified the dead people.

The site is one of Hanwha Aerospace’s key facilities where it develops large-sized propellants and surface-to-surface weapons systems, according to Yonhap news agency.