Incident comes days after an Air India plane crashed in the western Ahmedabad city, killing all but one of 242 on board.

All seven people on a helicopter in northern India were killed early on Sunday when it crashed while ferrying passengers on a popular Hindu pilgrimage route in the Himalayan state of Uttarakhand, officials said.

Officials from the US National Transportation Safety Board (NTSB) surveyed the site of Air India plane crash that killed at least 271 people, sources said on Sunday, with families continuing to wait for DNA profiling results to identify charred bodies.

Indian investigators have recovered the digital flight data recorder or the black box of the Air India flight that crashed a day earlier.

At the hospital in Ahmedabad, family members were giving DNA samples, waiting for official confirmation of their loss in the Air India disaster, and remembering their loved ones.