11 Children Killed By Gunman At School In Rio De Janeiro

"As many as 20 people are feared dead after a gunman invaded a primary school in Rio de Janeiro and opened fire," The Guardian reports. "One witness told the Guardian he had seen between 15 and 20 children dead or seriously wounded inside the Tasso da Silveira primary school in western Rio." [updated: Eleven children and the gunman are dead.]

Details are still coming in and reports vary. Sky News, citing Agence France Presse, says "13 people" were killed. The Associated Press writes that "Brazilian authorities say a gunman has injured at least 15 people."

We'll update as the story develops.

Update at 1:30 p.m. ET. More On The Death Toll And Shooter:

In a press conference, Sérgio Cabral, governor of the state of Rio, said 10 girls between the ages of 12 and 14 and one boy were killed by the gunman, who fired more than 100 bullets. Another 18 students were injured, some of whom are in serious condition.

The Spanish daily El Pais, reporting from Rio, says authorities have identified the gunman as Wellington Menezes de Olveira, a 23-year-old former student.

Uruguay's Observa reports that the gunman entered the Escola Municipal Tasso da Silveira at 8 a.m. He entered a classroom, told the students he was there to give a speech and started shooting.

"Without saying a thing, he took out a gun from his backpack and he started firing," Dorival Porto Rafael, a school administrator, told reporters.

El Pais reports that the alleged gunman was confronted by police who were already in the area. They cornered him on the second floor of the school and shot him in the leg.

The alleged gunman then shot himself in the head.

O Globo has cobbled up an extensive portrait of de Oliveira. He was a troubled young man, who was the adopted son of a family of five. A foster sister said the last time she saw de Olveira he was isolated and had grown a beard.

Authorities say de Olveira left a suicide note. El Pais reports on its contents:

The letter hasn't been made public. But according to Col. Djalman Beltrame, who commands the 14th batallion, the letter contained "fundamentalists themes and religious themes" and spoke of "terrorists practices."

Rio's police chief told O Globo did not have any prior criminal record.

Update at 11:49 a.m. ET. Brazilian President Presides Over Minute Of Silence:

Brazil's daily O Globo reports that a spokesman for President Dilma Rousseff said that upon hearing the news the president cried. After a public event celebrating entrepreneurs, Rousseff asked for a moment of silence.

"Today we mourn what happened in Realengo to defenseless children," she said. "Let's unite repudiating this act of violence, especially against defenseless children, children who lost their lives and their future."

The president of the Brazilian senate Jose Sarney said the shooting should raise questions about the state of security in Brazilian schools.

"It doesn't fit in our heads that this happens in our schools," O Globo quotes Sarney as saying. "In a sense, this is an act of terrorism."

Update at 10:28 a.m. ET. 'Unprecedented Tragedy In Brazil':

"The minister of Education, Fernando Haddad, said ... during a visit to the hospital in the city of Porto Alegre that the attack on ... a municipal school of Rio de January is an 'unprecedented tragedy in Brazil.' " Brazil's Globo News network reports.

Update at 10:17 a.m. ET. More On The Death Toll:

The Associated Press writes that "Brazilian authorities say that a gunman opened fire in an elementary school in Rio de Janeiro and at least 13 people are dead. The gunman is among them, though it is not clear if he shot himself or was killed by police."

Update at 10:10 a.m. ET. At Least 13 Reported Dead: Brazil's Globo news network reports that (according to this translation from Portuguese), the "Secretary of Health of Rio confirmed 13 deaths in shooting in school ... Ex-student invaded building in morning Thursday. Attack left more than 22 wounded and sniper died."