A fire at a lithium battery manufacturing factory near South Korea’s capital on Monday left at least 16 people dead, seven injured and six missing, officials said. Rescue workers at the factory in Hwaseong city, just south of Seoul, retrieved the bodies after combing through the site, local fire official Kim Jin-young told a televised briefing.

Kim earlier said most of the missing people were foreign nationals including Chinese. He said the mobile phone signals of the missing people were tracked to the second floor of the factory. A witness said the fire began after batteries exploded as workers were examining and packaging them. The exact cause will be investigated and officials will also check if fire extinguishing systems worked.