About 30 public school students in Santiago, Chile were injured Wednesday, five of them seriously, as they threw Molotov cocktails inside the school, authorities said.

“More than 30 students were injured,” summed up Education Minister Nicolas Kataldos during a press conference on the dramatic incident at the Internado Nacional Barros Arana (INBA) high school/high school.

Of the injured, five are in critical condition, Health Minister Jimena Aguilera clarified during the same press conference.

“Under circumstances that have not yet been ascertained, these mechanisms ignited, causing burns to a large number of students who were in the toilets” of the school, explained police officer Fernando Albornos.

According to media, the devices exploded at noon, as students were preparing a celebration for the end of the school year for their classmates who are in the last grade.

INBA is one of the oldest and best known public high schools in Santiago.

“Molotov cocktails are weapons,” Interior Minister Carolina Toa commented from the presidency, stressing that improvised incendiary devices of this kind cannot be “accepted during demonstrations.”

In recent years, students at this educational institution have organized several demonstrations, some of which have been marked by clashes with the police, to demand more resources for public education.