Police in China have ruled out terrorism as a motive for the mass killing of 19 people in a remote village in the south-western province of Yunnan.

The killings have shocked China, a country where mass murder is rare.

The official Xinhua news agency said 19 victims from six different families were found in different parts of the remote mountainous village of Yema.

At least three of those killed were children, including a three-year-old girl.

It is not clear exactly how they were killed or what the motive was.

Video being spread via social media appears to show a suspect being arrested at the scene, but authorities have said a man in his twenties was detained in the provincial capital Kunming, 200 kilometres away.

Yunnan police named him as 27-year-old Yang Qingpei.

So far police have not revealed a motive for the killings, but they have ruled out terrorism.

News dominates Chinese social media platforms

Mass killings are rare in China, and the news has dominated Chinese social media platforms.

Last year China executed three people for a mass stabbing at the Kunming railway station in which 31 people died.

More than 140 were injured in the rampage, which Chinese President Xi Jinping labelled a "violent terrorist" attack.

Xinhau said knife-wielding attackers dressed in black burst into the station on March 1, 2014, and began slashing indiscriminately.

State-run media dubbed it "China's 9/11".

Beijing blamed the bloodshed on "separatists" from the resource-rich far-western province of Xinjiang, where at least 200 people had died in attacks and clashes between locals and security forces in the year before.

ABC/wires