Police are searching mountainous woodlands in southwest China's Guangxi Zhuang Autonomous Region for a man suspected of killing four primary school kids on Friday.

More than 300 people, both police and civilians, have joined the manhunt, aided by sniffer dogs, in woods in Lingshan County, about 7 km from the crime scene.

Police have identified the suspect as a 56-year-old local man surnamed Shi.

Four primary school students were killed at around 6:20 a.m. in a knife attack on their way to Gupu Primary School. Three died at the scene and one died later in hospital.

Police have offered an award of up to 20,000 yuan (3,250 US dollars) for information. The search team is increasing as more police and civilians get involved.