Shimla, Jan 13 (IANS): The death toll in a road accident in the interiors of Himachal Pradesh's Shimla district has risen to 11 and 21 are injured, officials said Friday.

A state roadways bus carrying local passengers from Chopal town to Dharchana village skidded off the road and rolled down the hill near Kupvi, some 120 km from here, in Chopal subdivision Thursday evening.

Eight passengers were reported dead immediately after the accident. Now the number of dead has gone up to 11.

"The death toll could increase as the wreckage of the bus is yet to be retrieved (from the 300-ft-deep) gorge," Deputy Commissioner Onkar Sharma said.

Deputy Superintendent of Police N.S. Negi told IANS that 21 passengers were injured in the accident. "Some of them have been referred to a Chandigarh hospital while the rest have been admitted at zonal hospital in Paonta Sahib (in Sirmaur district)," he added.

The cause of the accident is yet to be ascertained, but the government has ordered a magisterial inquiry. The accident spot had recently experienced heavy snowfall.