Seven people were killed and 11 others injured after a private bus overturned and plunged onto a lower road in Himachal Pradesh's Chamba district on Saturday morning.

The accident took place at around 7.15 am near Chalunj Mor on the Bairagarh-Tissa road, when the bus was travelling from Bairagarh towards Chamba.

The 27-km mountain route through the remote Churah Valley is known for its narrow stretches and steep drop-offs and also forms part of the route towards the high-altitude Sach Pass.

According to police, the exact number of passengers travelling on the bus was not immediately known. Locals rushed to the spot after hearing passengers screaming for help and alerted the authorities.

A multi-agency rescue operation was subsequently launched, with personnel from the National Disaster Response Force, police, Home Guards, Fire Services and the Revenue Department working at the site.

Police said some passengers may still be trapped beneath the wreckage, raising concerns that the death toll could increase.

Of the 11 injured passengers, six who suffered serious injuries were referred to Pt Jawaharlal Nehru Government Medical College and Hospital in Chamba for further treatment.

The remaining injured passengers were taken to medical facilities for treatment.

Chamba Superintendent of Police Vijay Saklani said the cause of the accident has not yet been established. Police have begun an investigation into the circumstances that led to the bus overturning.

Local Pradhan Mandhi Rana also confirmed that rescue efforts were continuing at the accident site.

The crash comes amid a deadly monsoon season on Himachal Pradesh's roads. Police said 78 people have died in road accidents across the state between June 30 and August 7.