A soldier has killed 20 people and injured many more in a gun rampage in the Thai city of Nakhon Ratchasima in Thailand.

Jakraphanth Thomma, a junior officer, killed his commanding officer before stealing weapons from a military camp, a defence spokesman told BBC Thai.

The suspect then drove to the city centre and entered a shopping complex, where he is believed to be holed up. The suspect, whose motives remain unclear, posted images of his attack on social media sites.

It began in Nakhon Ratchasima, also known as Korat, in the late afternoon at the Suatham Phithak military camp, where the commanding officer, named by the Bangkok Post as Col Anantharot Krasae, was killed. The Post said a 63-year-old woman and another soldier were also killed there.

The suspect seized arms and ammunition from the camp before taking a Humvee-type vehicle. He then opened fire at a number of sites before arriving at the Terminal 21 shopping centre.

Local media footage appears to show the suspect getting out of his vehicle and firing shots as people flee. CCTV footage shows him inside the shopping centre with a raised rifle.

Other footage showed a fire outside the building, with some reports saying it was caused by a gas canister that exploded when it was hit with a bullet. One of the suspect’s social media posts features an image of himself with the fire in the background.

Authorities have sealed off the shopping centre as they try to track down the suspect, who is said to be inside the building. Police have warned people to stay at home.