Salem (Tamil Nadu) : At least four passengers were killed and twenty others were critically injured when a private bus plunged into a gorge in Yercaud in Tamil Nadu's Salem on Tuesday evening, the officials said.

According to the police, the private bus was heading to Salem from Yercaud with 56 passengers on board when the incident took place.

While the bus reached the 13th hairpin bend, the driver lost control of the vehicle in the turning, and the vehicle hit the sidewall.

After this, the bus fell into the gorge, and landed on the 11th hairpin bend, the officials added.

The injured were rushed to the hospital.

"Yercaud police have filed a complaint and investigation is going on," the police officials added.