The entrance of the Zoo Station on Subway Line 4 is closed after an escalator accident occured in Beijing Tuesday morning. [Photo/Xinhua]

BEIJING - One person has died and 28 others have been injured - two seriously -  after an escalator accident Tuesday at a Beijing subway stop.

The incident happened at 9:36 am at the A exit of the Zoo Station on Line 4, said the information office of the Beijing municipal government.

The office said some people on the escalator fell down after "an escalator malfunction," without elaborating the nature of the malfunction.

According to photos posted by witnesses on microblogs on weibo.com, several people were seen lying on the ground - apparently after falling down from the escalator - and were helped by others. Blood can be seen on the floor.

Beijing MTR Corporation, which operates the Line 4 subway, posted a brief statement about the accident on its website mtr.bj.cn, which provided an explanation as same as the government's press release.

The company said it has already launched an emergency response and all injured people have been sent to the hospital.

The government has demanded a probe into the accident while asking all subway operators to immediately launch checks of facilities to ensure the safety.