SEOUL, South Korea (AP) — Officials in South Korea say a fire at a lithium battery manufacturing factory near South Korea’s capital has left at least 16 people dead, seven injured and six missing.

Rescue workers at the factory in Hwaseong city, just south of Seoul, retrieved the bodies on Monday after combing through the site.

A local fire official said the mobile phone signals of the missing people were tracked to the second floor of the factory.

Kim said a witness told authorities that the fire began after batteries exploded as workers were examining and packaging them, but the exact cause would be investigated.