The coach-style bus landed upside down on the ice, collapsing the passenger compartment. (NY Post)

A passenger bus plunged off a bridge onto a frozen river in Siberia on Sunday, killing 19 of the more than 40 people on board, authorities said.

A tire on the bus burst as it was crossing the bridge over the Kuenga river in eastern Siberia’s Zabaikalsky region.

The vehicle, which was travelling from Sretensk to Chita and carried 40 passengers, skidded off the road and onto the ice.

“Nineteen people died and 21 received various injuries,” the office of the governor of the Zabaikalsky region said in a statement.

Two preschool-aged children were reportedly among the dead.

National television broadcast footage of the mangled wreckage of the bus, which lay upside down on the snow-covered ice surrounded by ambulances and fire engines.

Nineteen people including a 12-year-old girl were hospitalized.

More than 70 people and two helicopters with medics were involved in the rescue operation, officials said.

Prime Minister Dmitry Medvedev told his deputy Tatyana Golikova to do everything to help the families of the victims, the government said.

“The head of government expressed condolences to the families of those who died,” the government said in a statement.

The Investigative Committee, which probes serious incidents, said it had opened a criminal inquiry into a possible violation of traffic safety rules.

The head of the powerful Investigative Committee, which reports directly to President Vladimir Putin, demanded a “detailed investigation” into the deadly accident.

Officials said the driver — who died in the crash — had years of experience.

Local authorities launched a crowd-funding campaign to help the victims and their families.

Road accidents are common in Russia, often due to alcohol, the poor state of roads and failure to observe traffic rules.

However, the number of road deaths has gone down in recent years, to around 20,000 per year.