SHIJIAZHUANG - Sixteen people have been buried after a factory building collapsed on Monday in North China's Hebei province, local authorities said.

The obsolete building near the village of Houshan in Wuan city collapsed early in the morning, sources with the city's government said.

The buried, all construction workers for Fengshanbao Iron Mine, were staying in the building for the night, according to the sources.

The Wuan government has ordered all-out efforts to rescue the workers.

Meanwhile, an investigation into the cause of the collapse is under way.