At least 18 people died and 25 others were injured when a bus in which they were traveling rolled down into a 1000-feet deep gorge in Sirmaur district of Himachal Pradesh on Tuesday.

The incident took place late in the afternoon after the driver lost control of the vehicle while negotiating a sharp curve near Ganduri, 120 km from Sirmaur, Superintendent of Police J P Singh said.

There were about 50 people traveling in the bus which was on its way to Solan from Gatadhar in Sirmour, he said.

While injured have been admitted to Sirmour and Nahan hospitals, the critically wounded among them have been moved to Chandigarh.

This is the fourth major bus accident in Himachal Pradesh since November.

In November, 13 people were killed when a bus plunged into a gorge in Kullu.

In December, 14 people were killed in an accident near Solan.

On June 21,  a bus fell into a gorge in Kainchimode near Dharamsala, killing 11 people.