By Sunday night rescuers had successfully pulled out four more bodies from a collapsed subway tunnel in Beijing, while search for the last remaining worker continues.

The collapse happened at 9:30 AM on Wednesday at a construction site for the No. 10 subway line on the Haidian Nanlu Road between the third and fourth northern ring roads in the city's Haidian district.

Six workers were buried underground after the accident. Rescuers recovered the first body on Friday afternoon.

The site of the collapse was a pond 50 years ago, and the geological structure of the underground layer is loose, experts said.

Three rescue workers walk out of the cave-in site with their rescue dogs on Sunday morning, April 1, 2007.

A worker examines the collapsed site on Sunday, April 1, 2007.

A Beijing citizen places a flower bouquet near the site of the collapse to mourn the dead on Sunday afternoon, April 1, 2007.

(CRI April 2, 2007)