Thai security forces killed a soldier on Sunday after he carried out a shooting rampage in northeastern Thailand, police and military sources said.

The soldier who gunned down 27 people did it over a "personal problem," Thai Prime Minister Prayut Chan-O-cha said Sunday, adding that 51 others were injured.

Hostages were rescued from the gunman late Saturday in Nakhon Ratchasima, northeastern Thailand.

The killings began at around 15:00 local time (8:00 GMT) on Saturday when the soldier opened fire in a house before moving to an army camp and then to the mall, whole posting messages on Facebook.

"The gunman used a machine gun and shot innocent victims resulting in many injured and dead," AFP reported, citing a police spokesperson.

The gunman, identified as Jakkrapanth Thomma, held several people hostage inside the Terminal 21 shopping mall, but by 2:00 Sunday local time, police officials had announced that all civilians had been safely brought out of the mall.

The alleged killer, who is a soldier, stole a Humvee from his base and then proceeded to drive around the city on a shooting spree, media quoted police in the northeast as saying. 

The alleged shooter proceeded to shoot at shoppers inside a mall in the city. He took a selfie during the attack and posted it onto social media. 

(With input from agencies)