SHENZHEN - Eight students were injured, including four who are in critical condition, in an escalator accident at an amusement center in south China's Guangdong province on Wednesday.

The accident occurred around 3 p.m. at a children's amusement center in Luohu District, Shenzhen City.

A child fell down when some students from Longhua Shuxiang Elementary School were standing on an escalator on the third floor of the center, where students were taking part in an activity being held there, a tour guide responsible for the activity said.

The guide said a passerby saw the child fall, then pressed the emergency button to stop the escalator. This brought the escalator to an abrupt stop, which caused the other children to tumble down the escalator.

So far, eight children have been sent to hospital for treatment. Four of them are in critical condition, but their injuries are not life-threatening, according to local media reports.