A passenger bus today plunged into a glacier in Siberia, killing 19 of the more than 40 passengers on board.

A tire of a bus, traveling from Sretensk to Chita, exploded as it crossed a bridge on the Kuenga River in the Zabaikalsky region of Siberia. The car then slipped off the road and plunged into the frozen river.

"19 people died and 21 were injured at different levels," the regional governor's office Zabaikalsky said in a statement. Two helicopters and doctors were dispatched to the scene.

The Russian Investigation Commission said it is opening a criminal investigation to see if the driver violated traffic safety rules.

Road accidents are quite common in Russia, often caused by drunk driving, degraded road quality and drivers violating traffic safety regulations. However, the number of deaths due to road accidents in recent years has decreased, to about 20,000 each year.