Rescuers have been working hard to reach the six workers who have been trapped beneath the ground after a subway construction site collapsed but experts fear the hope of their survival is slim.

An official in charge of the rescue operation said the efforts to clear away the fallen ground were completed, and manpower would be soon sent down to look for the six missing.

In the meantime, the buildings in the vicinity and the underground pipelines of civilian use are closely monitored so that more unexpected situations will not occur.

Five of the six workers, who worked for the China Railway 12th Bureau Group Co. Ltd., a stated-owned construction company, are from Sichuan Province and one more from Henan Province, said sources from the municipal bureau of public security.

The accident occurred at 9:20?AM on Wednesday on the route of the No. 10 Subway Line which is under construction in Haidian Nanlu Road between the third and fourth North Ring Road in the city's northwestern Haidian District.

The collapsed section covers an area of about 20 square meters and is about 11 meters underground, rescuers said.

Cause of the collapse is under investigation.

(Xinhua News Agency March 29, 2007)