Beijing - Twenty-one people are feared dead after a cave-in at a tunnel under construction for a subway line in the eastern Chinese city of Hangzhou, state media said on Sunday. 

Rescuers had recovered three bodies by Sunday morning and held little hope of finding 18 missing construction workers alive, the official Xinhua news agency said. 

"There is a slim chance for the survival of trapped workers, because of heavy flooding in the crater," the agency quoted Wang Guangrong, a spokesman for the rescue services, as saying. 

The water in the hole left by the cave-in had fallen to about 3 metres after reaching 6 metres on Saturday, Wang said. 

A road caved in above the tunnel on Saturday afternoon, trapping construction workers and causing 11 vehicles to fall into a 15-metre- deep crater, about 75 metres long and 50 metres wide. 

Some 2,000 rescue workers were pumping water out of the hole left by the collapse, and divers had searched the site for survivors. 

Other state media reports showed photographs of cranes lifting vehicles out of the hole. 

Local hospitals treated at least 19 rescued people, including two in serious condition, while witnesses and rescuers earlier said at least 50 people were trapped. 

About 30 construction workers and 27 bus passengers managed to escape after the cave-in, the agency said. (dpa)