A 13-year-old boy was killed and 28 other people injured when an escalator at a Beijing subway station suddenly malfunctioned.
The rising escalator reportedly changed direction, sending more than 20 passengers crashing down and killing the teenager, who was on the way to the zoo with his father and sister.
It happened at the exit of Zoo Station and photos of the aftermath were posted by witnesses on Chinese microblogging wite Weibo.com.
The images show people lying on the ground at the bottom of the escalator.
It appears the boy and his family were crushed under others who fell.
His father is said to be in intensive care at the Peking University People's Hospital.
His sister suffered head injuries and is being treated at a children's hospital.
Beijing MTR Corporation, which operates the Line 4 subway, blamed an "escalator malfunction" and said it had launched an emergency response.
It also apologised to the injured and guaranteed medical treatment for those affected.
The city government has demanded an investigation and asked all subway operators to carry out checks of facilities to ensure their safety.