A Thai soldier has shot dead “many people” in and around city of Nakhon Ratchasima (also known as Korat), north-east of Bangkok, reports say.
A defence ministry spokesman told BBC Thai that Jakraphanth Thomma attacked his boss before opening fire at a military camp, a Buddhist temple and a shopping centre.
The suspect is hiding in the basement of the shopping centre, he added.
Local media are reporting at least 12 deaths.
The incident is still ongoing.
Posts on social media appear to show the scene of a shooting near a shopping centre.
