Rescue workers prepare to lift a bus after it was swallowed by an enormous sinkhole road collapse in China's northwestern Qinghai province. AFP

At least six people were killed in China after a bus plunged into a sinkhole on a city street in country's northwestern region.

Accident also left four missing, authorities said.

The collapse on Monday afternoon left 16 people in the hospital.

Some 1,000 emergency workers and 30 vehicles were sent to the site, the emergency management bureau in the city of Xining said.

A crane was called in to lift the bus above the sinkhole so rescue workers could look for victims.

Video apparently shot by security cameras just after the accident showed the bus gradually settling into the hole while people nearby scrambled for safety.

Other video showed the bus tipped more than halfway into the chasm that had opened up at a bus stop just outside a health clinic.

Light and smoke were coming to the surface, possibly as a result of the rupture of gas or electricity lines. Workers using backhoes, dump trucks and other equipment excavated earth around the collapse.

The the emergency management bureau said the bus had been raised from the collapsed 80-square-meter section into which it had fallen.

Associated Press