Beijing- A cave-in trapped at least 50 people on Saturday afternoon in a tunnel under construction for a subway line in the eastern Chinese city of Hangzhou, state media said.

A road caved in above the tunnel, trapping an unknown number of construction workers and causing several vehicles to fall into the hole, the official Xinhua news agency said.

About 2,000 rescue workers rushed to the site and were "struggling to pump water out of the tunnel", the agency quoted rescue officials as saying.

The exact number of people missing remained unknown, with at least 13 vehicles trapped in 15-metre-deep crater about 75 metres long and 50 metres wide, it said. (dpa)