One section of a bridge being built for the Indian capital's metro rail system collapsed Sunday, crushing to death five workers and injuring 13 in a major setback to the project that officials hope to complete before the 2010 Commonwealth Games.

New Delhi's landmark metro rail project is already operating three lines and is working around the clock to build several extensions. The metro is the pride of the city, where commuters were long forced to rely on smoke-belching buses, rickety three-wheel motorized rickshaws or their own motorcycles.

The project was particularly notable because it opened on schedule about seven years ago — an almost unheard of feat in India, where corruption-related overruns are common.

E. Sreedharan, the head of the Delhi Metro Rail Corp., has been hailed as a modern-day hero, but on Sunday, he tendered his resignation to take moral responsibility for the collapse, which is a rare blemish in the largely successful project.

"This is a very, very serious accident," said Sreedharan, an official known for his integrity and dedication. He said he sent his resignation letter to New Delhi Chief Minister Sheila Dikshit, who has not yet said whether she will accept it.

The accident occurred on a particularly tricky section, where a 2.5-mile (4-kilometer) metal cantilever was being raised to attach to a long section of concrete girders, all of which tumbled down in a V-shape pile.

The area — near the tony Greater Kailash neighborhood — was cordoned off and cranes worked to clear the rubble to reopen the road underneath. A high-powered committee, comprising engineers and experts was appointed to find the cause of the accident and submit its report with 10 days, Sreedharan said.

He said two workers died at the accident site and three at the hospital. Two of the 13 hospitalized workers are in serious condition while the rest suffered minor injuries.

Sreedharan noted the casualty toll could have been higher if the accident had not happened so early in the morning.

The metro's first three lines opened in 2002 and cover a total of 45 miles (75 kilometers). Authorities are rushing to complete several extensions totaling about 60 miles (100 kilometers) before the October 2010 Commonwealth Games. Sreedharan said the project would be delayed for at least three months.

The accident caused a damage worth 60 million rupees ($1.25 million), he said.

In October last year, two people were killed and at least 11 injured in a similar accident at a metro construction site.

The highly efficient and clean metro rail system is the third mass urban transport system in the country.