BANGKOK: A Thai teenager suspected of killing two foreigners in a Bangkok mall shooting had suffered a psychological breakdown and had modified a handgun designed to fire blanks, police said on Wednesday.

Chaos erupted at the luxury Siam Paragon mall close to peak hours on Tuesday, with hundreds fleeing as gunshots rang out in what was the latest high-profile gun violence to grip the country in the past three years.

Two women were killed, from China and Myanmar, and five people wounded - two foreigners and three Thai nationals.

The suspected gunman, a 14-year-old, was arrested late on Tuesday. Police said he had been receiving psychological treatment and had not taken his prescribed medication on the day of the shooting.

Investigators were looking into the boy's background and planned to speak to friends, who were online gamers, about his mental state, the national police chief said, adding it was unusual to apprehend a shooter alive.

"We will have to investigate the suspect as to whether he had violent and aggressive conduct before," police chief Torsak Sukvimol said in a television interview.

"The suspect had a breakdown psychologically and it fits an active shooter profile," Torsak said, adding he had questioned the detained boy.

"Initially I spoke to him to calm him down ... he appeared to hear someone speaking to him, he was hearing things, a noise he said told him to shoot."

GUN TROUBLES

Mass shootings are rare in Thailand but gun violence and gun ownership is common. Rules on ownership are strict, but firearms can be modified and obtained illegally, many smuggled from abroad.

The violence came three days from the first anniversary of the death of 35 people, including 22 children at a nursery in a northeast Thai town, during an hours-long gun-and-knife attack by a former policeman who later shot himself dead.

In 2020, a soldier shot and killed at least 29 people and wounded 57 in a rampage that spanned four locations around the northeastern city of Nakhon Ratchasima.

The latest shooting came at as a new government is trying to stimulate a stuttering economy by boosting tourist arrivals in what is one of Asia's most popular travel spots, including by offering visa-free entry to Chinese nationals.

Named the world's most photographed place by Instagram in 2013, Siam Paragon is Thailand's most famous mall, drawing throngs of domestic and foreign shoppers daily to its high-end stores, aquarium, cinema and food court dining.

Prime Minister Srettha Thavisin expressed condolences over the deaths in opening remarks at a technology event hosted by Siam Paragon, which reopened for business on Wednesday.

China is a crucial market for Thailand's tourism industry, accounting for a quarter of its record of nearly 40 million visitors in pre-pandemic 2019.

China's embassy in Bangkok expressed regret over the incident and said Srettha had called its ambassador to give assurances of a thorough investigation and to "strengthen public safety management to offer a reliable and safe environment for Chinese people traveling to Thailand".