Sikkim Avalanche: Videos from the site showed the magnitude of the tragedy.
Seven people, including a child and a woman, have been killed and many others are feared trapped under snow after a massive avalanche near Sikkim's Nathu La mountain pass today.
"23 tourists rescued till 4 PM including 6 from deep valley and shifted to nearby medical facilities of Indian Army. Unfortunately, seven persons have succumbed," the Army said in a statement.
Approximately 5-6 vehicles along with 20-30 tourists on way to Nathu La are feared to have been stuck under the snow, said the Army.
The avalanche struck around 11.10 AM at 15th Mile in Jawaharlal Nehru road connecting Gangtok with Nathu La when at least 150 tourists were in the area.
The search operation was called off in the evening due to inclement weather.
Prime Minister Narendra Modi tweeted saying "all possible assistance is being provided to those affected" and that he was distressed by the tragedy.
"Distressed by the avalanche in Sikkim. Condolences to those who have lost their loved ones. I hope the injured recover soon. Rescue ops are underway and all possible assistance is being provided to those affected," tweeted the Prime Minister.
Union Home Minister Amit Shah said the Centre was closely monitoring the situation.
"My sincerest condolences to the families of those who have lost their lives in the tragic avalanche in Sikkim. We are closely monitoring the situation and the teams of NDRF will reach the affected area soon. I pray for the speedy recovery of those injured," he tweeted.
Nathu La Pass, at a height of 4,310 metres (14,140 feet) above sea level, is situated on the border with China and is a major tourist destination.
Videos from the site showed the magnitude of the tragedy. Dozens of people could be seen involved in rescue operations and trying to dig out those who are trapped.
In one of the videos, someone is seen scooping up snow with a shovel as a man, half buried, looks up to be rescued.
Chief Minister Prem Singh Tamang condoled the deaths, and said that he was praying for the speedy recovery of those injured.
"My heart goes out to the bereaved family and friends in this hour of grief and I pray that the departed souls rest in eternal peace," Mr Tamang said.
Around 350 stranded tourists have also been rescued after snow was cleared from the road.
The East district has been experiencing rainfall and snowfall in the higher reaches since Friday, a weather official said.