BBC South Asia Correspondent Mike Wooldridge: Disaster at an increasingly popular annual pilgrimage

So far, 52 people are reported dead in the tragedy, and the death toll is expected to rise.

The landslide occurred while some 200,000 male Hindu pilgrims were gathered around the holy site on a hill.

The worshippers were watching for what they believed to be a celestial light at the Sabarimala shrine in Kerala state.

Deadly stampede

The BBC's Judy Swallow, who is in Kerala, said worshippers were trying to get the best vantage point of the celestial light when the hill collapsed under the sheer weight of pilgrims.

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Some of the dead were buried in the collapse, but most died in a stampede to avoid the landslide.

One police officer said: "There was panic all around, people were screaming. Most people died because they tried to rush down the hill."

Local emergency facilities in the remote region, which has little infrastructure, were severely stretched by the number of injured and some of the most critically injured needed to be transported further afield.

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Some of the bodies are proving hard to identify as there were also pilgrims from states other than Kerala.

The Indian Prime Minister, Atal Behari Vajpayee, is expected to visit the site of the disaster at some point.

Penance

Prime Minister Atal Behari Vajpayee said he was shocked by the tragedy.

During the two-month period of pilgrimage, millions of worshippers make their way to the shrine to the Hindu god Ayappa. Most are Hindus, but some Muslims also visit the site.

On their way back, they find vantage points on hilltops in the area to watch for the celestial light.

Devotees traditionally visit the shrine dressed in black robes at the end of a 40-day period of penance.

The BBC South Asia Correspondent, Mike Wooldridge, says it is the first time there has been such a tragedy at Sabarimala.

Indian pilgrimage sites, often located in isolated, inaccessible areas, have exerted a heavy death toll over the years, often as a result of devotees ignoring official warnings.

In 1996 more than 200 pilgrims died when they were caught in a blizzard en route to the sacred Amarnath cave site in the northern state of Kashmir.