At least 22 children and one adult have been injured in a knife attack outside a primary school in central China, police say.

An officer said the attack, in the village of Chengping in Henan province, happened shortly before 8am on Friday, as students were arriving for classes.

The attacker, believed to be 36-year-old villager Min Yingjun, is in police custody, said officials.

A county hospital administrator said the man first attacked an elderly woman, then students, before being subdued by security guards. Two students have since been transferred to "better-equipped" hospitals outside the county.

China has witnessed a spate of school stabbings in recent years, leading to more security guards being deployed across the vast country.

In March 2010, eight children were murdered in Nanping, Fujian province, by 41-year-old knifeman Zheng Minsheng. The attacker was executed a month later, hours before 33-year-old Chen Kangbing injured 16 students and a teacher at Hongfu Primary School in Leizhou, Guangdong.

In April 29 2010, 28 school children - mostly four-year-olds - were stabbed alongside two teachers and a security guard in Taixing, Jiangsu. On April 30, Wang Yonglai committed suicide after using a hammer to attack preschool children in Weifang, Shandong.

Further attacks in the months and years following have left 11 children and four adults dead, and several more injured.

Source: Al Jazeera and agencies