A 13-year-old boy was arrested by police after he allegedly decapitated his mother and posted a video of the murder online, Chinese media reports say.

The boy was from Dazhu County in China's south-western Sichuan province.

Chinese news site The Paper broke the news on Wednesday (Dec 6), saying it had received word that a boy in Dazhu country had murdered his mother.

A resident told The Paper that the boy was a student at a secondary school and lived with his grandparents.

He allegedly posted a video of himself murdering his mother and posted it on WeChat, Radio Free Asia Chinese news channel reported.

He then went to school as usual, where he was later arrested. A parent of one of his friends saw the video and made a police report.

In a statement to the media on Friday, Dazhu authorities said police received a report on Dec 5 regarding a 43-year-old woman who was allegedly murdered at home.

She was named only as Ms Chen. The suspect, Ms Chen's 13-year-old son, has been arrested, authorities said.

Preliminary investigations show that the suspect hated his mother as her "disciplining was too strict" and killed her with a knife.

Police investigations are under way.