The landslide struck early in the morning local time, leaving a bus and several vehicles trapped on the mountainside road.
Photos from the scene show rescuers navigating crushed vehicle parts, overturned cars, and strewn debris, with parts of the road completely blocked by loose dirt falling from the mountain.
Search and rescue teams from the Indian National Disaster Response Force and other emergency agencies were immediately deployed to the site, and operations continued overnight. More than 200 people continued to work along the stretch of National Highway 5, which connects northern India with the border with China, according to Reuters.
So far, 13 people have been rescued, an Indo-Tibetan Border Police spokesman said on Thursday. More than 20 people are still missing, he said.
“The rubble fell from quite high up,” local police chief Saju Ram Rana told Reuters, adding that heavy machinery was being brought in to clear the area.
“The devastating tragedy in Kinnaur is very sad,” Prime Minister Narendra Modi tweeted on Wednesday night. “In this hour of pain, my thoughts are with the families of those who lost their lives. May the injured recover as soon as possible.”
In the last month, India recorded dozens of deaths due to landslides caused by heavy rains. In July, at least 31 people were killed in two landslides in Mumbai.