Watch: Six killed, four missing after huge sinkhole swallows bus in China

Beijing: An enormous sinkhole swallowed a bus and pedestrians in northwest China, sparking an explosion, killing six people and leaving four more missings, state media said Tuesday.

Footage showed people at a bus stop running from the collapsing road as the vehicle -- jutting into the air -- sank into the ground.

Several people disappeared into the sinkhole as it spread, including what appeared to be a child.

The incident also triggered an explosion inside the hole, the video showed.

Sinkholes are not unknown in China, where they are often blamed on construction works and the country's rapid pace of development.

The incident occurred at around 5:30 pm (0930 GMT) on Monday in Xining, the capital of Qinghai province, the state-run broadcaster CCTV said.

A search and rescue operation involving more than 1,000 people and 30 vehicles was underway, according to the official Xinhua news agency.

An investigation into the cause has been opened.

Video footage published by state broadcaster CGTN showed a person being pulled from the hole by rescue workers.

The collapse left an 80-square-metre (860-square-foot) pit in the street outside a hospital.

The 16 injured were taken to hospital and are in a stable condition, Xinhua added, citing a local emergency management official.

An earlier report indicated that 10 people were missing but Xinhua said four were unaccounted for.

In 2016, at least three people fell into a huge sinkhole in central Henan province, which swallowed a section of road and passersby.

An initial investigation showed the collapse might have been caused by water pipes buried under the road breaking up due to the rain.

In 2013, five people died when a 10-metre (33-foot) wide sinkhole opened up at the gates of an industrial estate in Shenzhen.