CHONGQING -- Three passengers were killed and 46 were injured when a bus plunged down a 20-meter slope in southwest China's Chongqing Municipality, local government said Tuesday.

The bus, with 49 people aboard, ran off the road in Changling Town, Wanzhou District, and skidded 30 meters across a buffer area before plunging down the slope around 3:00 p.m. on Tuesday, said Wu Qiyong, director of the work safety bureau of Wanzhou District, Chongqing.

The bus was from Zhuhai city in south China's Guangdong province to Wanzhou.

Three people died at the scene. One of the injured was in serious condition, according to Wu.

The injured have been taken to hospital.

The cause of the accident is being investigated.