NEW DELHI, June 5 (Xinhua) -- At least nine people were killed and 21 others injured Tuesday after a bus carrying them skidded off a mountainous road and fell into gorge in India's northeastern state of Mizoram, officials said.

The accident took place at village Pangzawl in Lunglei district, about 169 km south of Aizawal, the capital city of Mizoram.

"This morning a bus carrying passengers fell into a deep gorge here, killing nine people on spot and injuring 21 others," personal assistant of deputy commissioner Lunglei told Xinhua over telephone. "Of the 21 injured, the condition of two is stated to be critical."

Following the accident, police teams were rushed to the spot to carry out rescue work.

The injured were rushed to a nearby hospital.

According to officials, the private bus was on the way to neighbouring Siaha district.

Police have registered a case and ordered investigations to ascertain reasons behind the accident.

Deadly road accidents are common in India often caused by overloading, bad condition of roads and reckless driving. Officials say on an average over 400 deaths take place every day in India due to road accidents.