A bus carrying Argentine border patrol officers crashed into a ravine in the northern province of Salta on Monday, killing 43 people.
“The bus fell about 59 feet,” said Francisco Marinaro, a provincial emergency official, in a TV interview from the scene, where an overturned bus was shown swarmed with emergency workers. Marinaro said that nine others were injured and being treated.
The vehicle was part of a three-bus convoy carrying officers of Argentina's gendarmerie, which patrols the country's borders. Salta borders Bolivia, Chile and Paraguay.
Passengers on the other two buses were the first people on site to attempt to save the officers trapped in the wreckage, officials said.
Security Minister Patricia Bullrich, who later toured the scene, told reporters that an initial investigation found that a right tire of the bus ruptured, causing the accident.
"This is a tragedy. We are going to work to make sure gendarmes are better equipped," Bullrich said.
Border security has become a hot issue in Argentina as the country has emerged as part of a route used for smuggling Andean cocaine to Europe and for human traffickers sending Syrian refugees to the Western Hemisphere.
The group was heading to the province of Jujuy, the country's most northern region that borders Bolivia.
Roads in Argentina, a large country with a land mass about four times the U.S. state of Texas, are poorly maintained in many rural areas.
The crash comes as President Mauricio Macri begins his first full week in office. He issued a statement offering condolences to the families of the victims.
"It's for this reason that we need to improve the roads so that this doesn't keep happening," the statement read.