A Brazilian gunman killed 11 children at a Rio de Janeiro school and then himself, police said Thursday, shocking the South American nation that has never seen such an incident before.

Brazilian President Dilma Rousseff wept when commenting on the incident during a speech to business leaders and requested a moment of silence for the victims.

“This type of crime is not characteristic of [our] country,” Rousseff said, “and therefore we are all ... united in repudiating this act of violence.”

The attack by the 24-year-old Welington de Oliveira was the first serial killing of its kind in Brazil. Attacks similar to the 2007 Virginia Tech massacre and the 1999 Columbine high school shooting in Colorado were unheard of in the South American nation.

“We have to show solidarity and support for the families of the children [killed by] that psychopath, that animal,” said Rio de Janeiro Governor Sergio Cabral in a press conference at the school in the Rio neighborhood of Realengo.

Oliveira was a former student at the school but his motive was not clear. Police said he did not have a criminal record. They said Oliveira entered the school carrying two guns and a suicide note. Oliveira told officials he was there to deliver a speech and then opened fire on students.