Police in Thailand said that they were on the hunt for a soldier in the Thai Army who opened fire and killed at least 20 people and injured many others.

The shooting took place in Thailand’s Nakhon Ratchasima Province, also known as Korat, on Saturday.

“At the moment, we are trying to capture the guy. Both police and military forces have been deployed to the area,” Krissana Pattanacharoen, a police spokesperson, told CNN.

The suspect, Sub. Lt. Jakraphanth Thomma, is a junior officer who allegedly shot and killed his commanding officer before stealing weapons from a military base, BBC News reported.

Pattanacharoen said the gunman’s motive remains unknown at this point of the investigation, but the suspect did post images of his attack on social media.

He wrote a post on Facebook earlier in the day saying, “Death is inevitable for everyone,” and posted a picture of what looked like his hand holding a gun. At one point after the shooting rampage began, he allegedly wrote, “Should I give up?” before the posts and his account became inaccessible, Al Jazeera News reported.

The attack began at the Suatham Phithak military camp, where the commanding officer, identified as Col. Anantharot Krasae, was killed. A 63-year-old woman and another man were also killed at the military camp.

The suspect seized guns and ammunition before fleeing the scene in a Humvee and opening fire at different places along the way before he arrived at the Terminal 21 shopping center.

Local media reports say the suspect got out of his vehicle and opened fire as people fled.

CCTV footage shows the alleged gunman inside the shopping center with a rifle.

Defence ministry spokesman Lt Gen Kongcheep Tantravanich said 20 people were among the dead.

Authorities have closed off the shopping center in their attempt to track down the suspect, who is believed to be inside the building. Police have issued warnings to people to stay at home.

Thailand’s Prime Minister Prayut Chan-o-cha tweeted condolences to the families of those killed or injured during the attack.