At least 20 people were killed and many injured on Saturday in a gun rampage in Thailand’s Nakhon Ratchasima city, according to the police.

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

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.

Public Health Minister Anutin Charnvirakul told media at the scene that one member of the security forces was killed and two wounded in the raid. As he spoke, a series of explosions and further shooting echoed from the Terminal 21 mall.

Police closed off streets around the mall and kept journalists behind a security cordon.

It has been reported earlier that the suspect, who it said was 32 years old, had taken hostages, but this has not been officially confirmed, The Bangkok Post said.

The suspect’s mother has been brought to the shopping centre to try to persuade him to give himself up.

Defence ministry spokesman Lt. Gen. Kongcheep Tantravanich said 20 people had been killed so far.

Prime Minister Prayuth Chan-Ocha is following developments and expressed condolences to the families of those killed, a spokeswoman said.

The public health minister has put out an appeal for people to donate blood at hospitals in the area.

He posted on his social media accounts during the attack, with one post on Facebook asking whether he should surrender.

The gunman was killed by the police on Sunday, according to the senior police official.

he news was confirmed by National Police chief Pol Gen Chakthip Chaijinda, The Nation newspaper reported.

The gunman, Jakraphanth Thomma, a junior officer, was hiding in the Terminal 21 shopping mall in the city also known as Korat following the shooting spree on Saturday evening, Chaijinda added.

The shooting spree began at around 3.30 pm on Saturday at the Suatham Phithak military camp, where Thomma first killed his commanding officer, named by the Bangkok Post as Col Anantharot Krasae.

A police officer contacted by phone in the city of Nakhon Ratchasima said the soldier initially shot dead another soldier and a woman and wounded a third person, apparently over a land dispute. Nakhon Ratchasima is also known as Korat.

City and neighbourhood police officers, who asked not to be identified because they were not authorized to release information, said the man took a gun from his base and drove to the Terminal 21 Korat mall, shooting along the way. Several Thai media reported that he travelled in a military vehicle.

Terminal 21 Korat is part of a small chain of Thai shopping centres run by Bangkok-based property developer LH Mall & Hotel Co. The malls feature floors modelled after major cities around the world.

Many malls in Thailand, including Terminal 21’s namesake in Bangkok, have metal detectors and security cameras at entrances manned by uniformed but unarmed security guards. Checks on those entering are often cursory at best.

(With inputs from agency)