XINING, Jan. 7 -- Two people were killed and 28 others were injured after two buses collided in northwest China's Qinghai Province, said local police on Wednesday.

A gray bus driving from Qinghai's capital, Xining, to Huangnan Tibetan Autonomous Prefecture collided with a white bus in Jainca County at 1:10 p.m. Wednesday and rolled into a nearby river.

The driver of the gray bus and a passenger died at the scene. Another 28 were injured and sent to hospitals, five of whom are in critical condition.

Police didn't disclose the number of passengers in the two vehicles.

An investigation into the accident is under way.