NEW DELHI - ONE person was killed and 17 others injured on early Sunday after a bridge being built to extend New Delhi's six-year-old metro system collapsed onto a bus and cars, police said.

Confirming the toll, Delhi police spokesman Rajan Bhagat told wires agencies rescue efforts to free people still trapped in the rubble were underway.

Television reports, meanwhile, said at least two people had died and added that the toll was expected to rise.

A 150m section of the bridge came crashing down, trapping a passenger-filled bus in the eastern part of the Indian capital, the Press Trust of India news agency said.

Metro official Vijay Anand told reporters at the site the accident was due to a 'technical failure' and that an inquiry would be carried out.

Television footage showed massive crowds gathered around huge metal girders that lay haphazardly on the ground.

New Delhi launched its metro system in 2002, and its cleanliness and efficiency have been frequently lauded by officials and visitors to the city.

Metro authorities are under severe pressure to get new train lines up and running by 2010, when Delhi will host the Commonwealth Games, and construction has been taking place night and day. -- AFP