Thousands of people holding candles attended a vigil in northeastern Thailand on Sunday for the victims of a mass shooting by a rogue soldier who killed at least 29 people and wounded 57 others before being shot dead.

Monks led prayers as people laid down white flowers in memory of the victims at the vigil, which was held by the statue of a historic local heroine, Thao Suranari, in the city of Nakhon Ratchasima. Some shed tears as they remembered the dead.

Bouquets of flowers, accompanied by written notes of condolence, were laid in front of Terminal 21 shopping mall in Nakhon Ratchasima city for mourning of the victims of the mass shooting.

Justice Minister Somsak Thepsuthin reportedly said on Sunday that an operation center has been urgently set up in Nakhon Ratchasima province, to provide assistance to victims of the shooting rampage.

Victims' relatives will be contacted and concerned offices will be coordinated to participate in providing them with assistance in accordance with the law, on compensation for damaged parties in criminal cases, according to director of the provincial justice office Vichien Chaiyason.

The killings began at around 15:00 local time (0800 GMT) on Saturday when the soldier opened fire in a house before moving to an army camp and then to the mall, where he shot bystanders as he moved inside.

The soldier, identified as 32-year-old Jakrapanth Thomma, was finally shot dead by security forces early on Sunday in the basement of the mall. Most of the victims were killed at the city's Terminal 21 shopping center, where the shooter held out against an overnight siege with an assault rifle and ammunition stolen from his army base.

Prime Minister of Thailand Prayuth Chan-ocha traveled to Nakhon Ratchasima on Sunday to meet wounded survivors, and told reporters from there that "it was a personal conflict... over a house deal."

Authorities are still piecing together details of the killing.