More than 50 people, mostly children, were injured by a man who broke into a kindergarten in south-western China and sprayed them with corrosive liquid, local authorities said Tuesday.

The suspect, a 23-year-old surnamed Kong, entered the kindergarten by climbing a wall before spraying victims with sodium hydroxide, said police authorities in Kaiyuan city, Yunnan province.

Police said Kong had intended to take revenge on society after growing up with divorced parents and then encountering difficulties in work and life.

The attack reportedly happened in Kaiyuan Dongcheng Kindergarten (pictured) in China

The attack took place on Monday at 3:35 pm (0735 GMT), Kaiyuan Public Security Bureau said on their Twitter-like Weibo account.

Local reports claimed the violence happened in Kaiyuan Dongcheng Kindergarten.

Some 51 children and three teachers were admitted to hospital for treatment, two with 'severe symptoms'.

Police arrested Kong less than an hour after the assault.

'Because his parents divorced during his childhood, the lack of family warmth resulted in psychological distortion,' said police, adding that Zhang's work and life were unsatisfactory as well.

The incident occurred in Kaiyuan in Yunnan Province near the Chinese border with Vietnam

All this created a 'pessimistic mentality and thoughts about retaliating against society', they said.

Violent incidents targeting schoolchildren are not uncommon in China, which has seen a slew of deadly incidents over the past few years - usually involving knives.

Mourners light candles during a vigil at the site of a knife attack which left two children dead in Shanghai in 2018. Attacks by society outcasts against children are not uncommon in China

In April last year, a 28-year-old man killed nine middle-school students as they were returning home in one of the country's deadliest knife attacks in recent years.

The killer, who said he had been bullied when he attended the school in northern China's Shaanxi province, was executed in September last year.

Later in 2018, a knife-wielding woman injured 14 children at a kindergarten in Sichuan province.

The 39-year-old assailant slashed students while they were returning to the classroom after morning exercises.