Shimla, Jul 16 (IANS): A pilgrim from Gujarat died following a heart attack during the Shrikhand Mahadev pilgrimage, one of India's toughest treks, in Himachal Pradesh's Kullu district, officials said on Monday.

The devotee, identified as Rajender Kumar, 55, was with his wife and son.

The first batch of the pilgrims for Shrikhand Mahadev, a rock Shiva lingam, left for the 30-km arduous trek on Sunday from the Singhad base camp.

No devotee is allowed to scale the Shrikhand Mahadev peak at an altitude of 17,600 feet without medical examination, an official told IANS.

To ensure safety, the pilgrims have to get themselves registered with the police before embarking on the journey.

Pilgrims and trekkers start their journey from Jaon, some 150 km from Shimla.

The pilgrims negotiate rugged, cold and inhospitable terrain, which takes at least three days, and conclude their journey at the Shrikhand Mahadev peak where they pay obeisance to the 72-foot tall Lingam.

The pilgrimage will officially continue until July 31. THe authorities expect around 20,000 devotees.

It is believed that Lord Shiva meditated in Shrikhand and that the Pandvas too had trekked to the peak during their exile.