SANTIAGO, Chile — A homemade firebomb exploded inside a public high school in Chile on Wednesday, igniting a blaze that injured at least 34 students and one teacher, with several in serious condition, firefighters said.

A group of students ages 15 to 18 at the school in central Santiago, the capital, were making Molotov cocktails in a bathroom to be thrown at a protest later when one exploded, said police Lt. Col. Fernando Albornoz. It was not clear what caused the blast. Police said they found bottles and fuel cans likely to make the explosives.

Fire department Capt. José Manuel Estefane said 11 students at the prestigious Barros Arana National Boarding School were hospitalized in serious condition with burns affecting their respiratory systems.

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The other injured students had lighter burns, authorities said, while a teacher trying to help the students collapsed and was hospitalized. Firefighters quickly contained the blaze and blocked roads around the scene.

Local media reported that the students had planned to wreak havoc at a traditional farewell party for graduating seniors.

High schools and universities across Chile have a history of activism stretching back decades. During major social unrest in 2011 and 2019, students, including at the Barros Arana school, took a confrontational stance against the government and business elite to demand political reforms.

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PHOTOS: Molotov cocktail explodes in a Chilean high school, injuring at least 35

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