A STAIRCASE guardrail in a northern China middle school collapsed Monday while students were leaving, killing at least 21 and injuring 47.

　　The accident at the No. 2 Middle School in Fengzhen, a city in the Inner Mongolia Autonomous Region, happened at 6:50 p.m.

　　A guardrail along stairway on the second floor inside the building gave way while students poured out of classes in the dark.

　　The Central Government said yesterday it was deeply concerned at the tragedy and ordered an immediate investigation.

　　An unidentified officer at Fengzhen Municipal Public Security Bureau said students behind those hurt in the initial collapse did not see what happened and kept pushing forward.

　　More than 260 medical workers and 12 ambulances responded to the accident. Special teams were assembled to investigate the cause.

　　(SD-Agencies)