At least 16 Hindu pilgrims were killed and 27 injured today after a bus they were travelling in skidded off a mountain road and fell into a gorge in Indian Kashmir, a senior police official said.

The bus was heading towards Srinagar, the state capital, when it veered off the mountainous road in the Kashmir Valley, Mohan Lal, senior superintendent of police, told Reuters.

Police and air force have launched a rescue operation and have so far airlifted 19 injured pilgrims, with some of them in critical condition, Lal said.

In a Tweet, Prime Minister Narendra Modi expressed his condolences on the loss of lives.

Hundreds of thousands of Hindus visit the Amarnath cave deep in the Himalayas in the months of July and August every year.

Last week seven Hindu pilgrims, most of them women, were killed in a gun battle that erupted in Indian Kashmir following two militant attacks on police, stoking outrage and protests nationwide.

Both India and Pakistan claim Kashmir in full, but govern separate parts, and have fought three wars since independence from Britain in 1947, two of them over Kashmir.