BUENOS AIRES, (AA): A bus crash killed 43 border patrol officers Monday in the northern Argentine province of Salta.

The bus fell off a bridge on Highway 34 near the city of Rosario de la Frontera, the governor of the province, Juan Manuel Urtubey, said in a statement.

“They gave their lives for their country, doing their duty,” he said.

The bus was carrying 50 officers to beef up security in the neighboring province of Jujuy after a rise of social tension and street violence there.

The survivors were taken to a hospital in Salta, capital of the province of the same name, according to the statement.

Jujuy Governor Gerardo Morales traveled to visit the injured with Urtubey in Salta, where he said in a separate statement that they were “doing well”.

Argentine President Mauricio Macri declared 24 hours of national mourning.

“We must all pay our condolences to the families” of the deceased, Macri said in a televised press conference.

National Security Minister Patricia Bullrich, who traveled to the scene of the accident, said the first indications suggested that a tire blowout had caused the bus to swerve and fall off the bridge.

“We are waiting for the official and final report in the next few days and then we can say exactly what had happened,” she said in a statement.