GUWAHATI: An avalanche killed at least seven tourists in India's Himalayan state of Sikkim near a mountain pass to the Chinese region of Tibet, with several more people feared trapped, the Indian army said.

The army said five to six vehicles carrying up to 30 tourists to the strategically located Nathu La pass between Sikkim and Tibet were feared to have been stuck under the snow when the avalanche hit.

"We are yet to ascertain how many people are still trapped. 17 people have been rescued, out of which 8 are very critical and have been moved to a hospital," senior police official Tenzing Loden Lepcha told Reuters on phone.

The incident took place at 11:30 a.m. (0600 GMT), the army statement said. Rescue officials earlier said they feared at least 70 people were under the snow at the site, some 40 km (25 miles) from the state capital Gangtok.

Rescue operations were ongoing, Loden Lepcha said, adding that when the avalanche hit, people were taking photographs near a stream. Rescue workers dug with shovels near a waterfall, images released by India's ministry of defence showed.

Yellow heavy machinery worked to clear the churned up snow left by the avalanche, the images showed.

An additional 350 stranded tourists and 80 vehicles were rescued after the snow was cleared from the road, the army statement said.

Thousands of tourists flock to Sikkim every year, also known as the "Land of Mystic Splendour", located below Mount Khangchendzonga, also known as Kanchenjunga, the third highest mountain in the world.

Nathu La serves as a route for the Kailash Mansarovar pilgrimage to Mount Kailash in China, considered one of the holiest pilgrimages in Hinduism.

The 3,500 km (2,100 miles) Himalayan border between India and China has been disputed since the 1950s. Both countries have raced to improve roads and railways in remote regions in recent years.

Avalanches and flash flooding in the Himalayas are common during summer and monsoon months, as snow melt and heavy rains combine.

In June 2013, record monsoon rains in the northern Himalayan state of Uttarakhand caused devastating floods that claimed close to 6,000 lives, one of the worst natural disasters to strike in the country.