At least 27 children and three adults were killed when a school bus plunged off a mountain road in the northern Indian state of Himachal Pradesh on Monday, officials say.

The tragedy occurred when the bus carrying 40 people swerved off the road and fell some 60 metres into a gorge before hitting the ground. 

The bus was transporting children, all below the age of 13, who were studying at a private school in Nurpur town, 300 kilometres from Shimla, the state capital.

The adult dead included two teachers and the driver.

TRT World spoke to Mumbai-based journalist, Rebecca Bundhun.

Several students are reportedly fighting for their lives in nearby hospitals.

"We have identified all the children and parents have been informed about the disaster," said Ram Nath Singh, a police officer at the accident site.

The state government has announced $7,700 (500,000 Indian rupees) in compensation for each victim's family.

PM Modi expresses "deep anguish"

Singh said three children with head injuries were taken to a government hospital.

India's roads, particularly in the hills, have long been feared for their deep potholes, reckless drivers and, very often, a lack of guardrails. Fatal accidents are common.

Prime Minister Narendra Modi expressed his deep anguish over the tragedy. "My prayers and solidarity with those who lost their near and dear ones in the accident," he said in a tweet. 

"I am deeply anguished by the loss of lives," Prime Minister Narendra Modi said in a tweet."My prayers and solidarity with those who lost their near and dear ones."

India has the world’s deadliest roads, with almost 150,000 people killed in accidents in 2015, the latest government data shows.