Two masked men armed with guns, knives, axes and crossbows descended on a school in southern Brazil on Wednesday, killing five students and two adults before taking their own lives, authorities said.
The men, identified as former students at the school in a suburb of Sao Paulo, also shot and killed the owner of a used car business nearby before launching the attack on the school, authorities said.
Besides the five students, the dead included a teacher and a school administrator, said Joao Camilo Pires de Campos, the state's public secretary. Nine others were wounded in the school attack and hospitalised, he said.
"This is the saddest day of my life," de Campos said, speaking to reporters outside the school in the Sao Paulo suburb of Suzano.
Authorities identified the attackers as 17-year-old Guilherme Taucci Monteiro and 25-year-old Henrique de Castro.
"The big question is: what was the motivation of these former students?" de Castro said.
Minutes before the attack, Monteiro had posted 26 photos on his Facebook page, included several with guns and one that showed him giving the middle finger as he looked into the camera.
In some of the photos, he wore a black scarf with a white imprint of a skull and cross bones. No text accompanied the posts.
By Wednesday afternoon, Facebook had taken down Monteiro's page.During the attack, Monteiro opened fire with a .38 calibre handgun and de Castro used a crossbow, de Campos said, adding that forensics would determine how each of the victims died.
The attackers were also carrying Molotov cocktails, knives and small axes, authorities said.
"In 34 years as a policeman, it's the first time I see someone use a crossbow like that," police Col. Marcelo Salles said. "It is horrendous."
The assailants were trying to force their way inside a room at the back of the school where many students were hiding when police arrived. Instead of facing police, they turned their weapons on themselves, authorities said without elaborating.
Students gathered outside the school recounted harrowing attacks and seeing several bodies lying in pools of blood.
Kelly Milene Guerra Cardoso, 16, said she and other students took refuge in the school's cafeteria, locked the door and lay on the floor.
"We stayed there until the door was opened. We thought it was the shooters coming to get us, but it was the police," she said. "They told us to start running."
Horacio Pereira Nunes, a retiree whose house is next to the school, said he heard shots around 10am.
"Then a lot of kids started running out, all screaming," he said. "It didn't take long until police arrived."
The Raul Brasil Professor public school has more than 1600 students from elementary to high school grades, teachers gathered outside said.
Latin America's most populous nation has the largest number of annual homicides in the world, but school shootings are rare.
In 2011, 12 students were killed by a gunman who roamed the halls of a school in Rio de Janeiro, shooting at them.
President Jair Bolsonaro ran on a platform that included promises to crack down on criminals, in part by expanding public access to guns. Soon after his January 1 inauguration, Bolsonaro issued a decree making it easier to buy a gun.
"A monstrosity and cowardness without equal," Bolsonaro wrote in a tweet expressing his sympathies for the families of the victims of Wednesday's attacks.
Similar to arguments made by proponents of less gun regulation in the United States, Bolsonaro and his supporters argue that expanded access to guns will combat crime.Sen. Major Olimpio, a member of Bolsonaro's party and a proponent of loosening gun legislation, again made that argument hours after Wednesday's rampage.
"We can't let those who take advantage of this tragedy speak about how disarmament is the solution," he tweeted, adding: "Weak and shameful 'disarmament farce,' which gave guns to criminals and prevented self-defense."