SRINAGAR, India, July 9

At least 13 people were killed when sudden rains triggered flash floods during an annual Hindu pilgrimage to an icy Himalayan cave in Indian-controlled Kashmir on Friday, police said.

Officials said in addition to the deaths, at least three dozen people were missing while an unspecified number of injured devotees were airlifted to hospitals for treatment. Authorities rushed several teams of doctors and paramedics to the rugged area and were administering first aid to the injured.

The heavy rain Friday evening near the mountain cave revered by Hindus sent a wall of water down a gorge and swept away about two dozen camps and two makeshift kitchens, officials said. An estimated 10,000 people were in the mountains when the rains struck.

The region's disaster management department said emergency workers were searching for missing people despite inclement weather.

T he Amarnath pilgrimage began on June 30 and tens of thousands of pilgrims have already visited the cave shrine where Hindus worship Lingam, a naturally formed ice stalagmite, as an incarnation of Shiva, the Hindu god of destruction and regeneration.

Hundreds of thousands of Hindus from across India take part in the pilgrimage, which lasts up to 45 days. Groups of pilgrims are staggered over a month and a half for security and logistical reasons.

This year, officials expect nearly 1 million visitors after a two-year gap in the annual endeavor due to the coronavirus pandemic.

India Prime Minister Narendra Modi expressed anguish over the deaths and said in a tweet that 'all possible assistance is being provided to the affected.'

Worshippers trek to the cave along two routes through lush green meadows and rocky and forested mountain passes with a view of glacial lakes and snowy peaks. A traditional route via the southern hill resort of Pahalgam that takes three days while a trip through northeastern Baltal lasts one day. Some pilgrims use helicopter services to make quick visits.

The cave, at 13,500 feet (4,115 meters) above sea level, is covered with snow most of the year except for the short summer period when it is open to pilgrims.

Hundreds of pilgrims have died in the past due to exhaustion and exposure to harsh weather during the journey through the icy mountains. In 1996, thousands of people were caught in a freak snowstorm during their trek, leading to more than 250 fatalities.

The pilgrimage concludes on Aug. 11, a full-moon night that Hindus say commemorates Shiva revealing the secret of the creation of the universe.

Apart from weather-related hazards, officials have said that pilgrims face an increased threat of attacks from Muslim rebels who have fought for decades against Indian rule. This year, for the first time, devotees are tagged with a wireless tracking system. Tens of thousands of police and soldiers guard the pilgrimage routes.

The pilgrimage has been targeted in past attacks by suspected rebels who accuse Hindu-majority India of using it as a political statement to bolster its claim on the Muslim-majority disputed region.

At least 50 pilgrims have been killed in three dozen attacks blamed on militants since an armed rebellion began in Indian-controlled Kashmir in 1989 for the region's independence or a merger with Pakistan, which controls a part of the territory.