Twelve children killed at a school in Rio de Janeiro

A man has killed at least 12 children and injured 11 others in a gun attack at a school in Rio De Janeiro in Brazil.

Police have named the gunman as 24-year-old Wellington Menezes de Oliveira, a former pupil at the Tasso da Silveira primary school.

Detectives said he entered a classroom armed with two loaded revolvers and opened fire soon after the morning bell rang.

He was later shot in the leg by police before taking his own life.

Police confirmed several children were badly hurt and were taken to the Albert Schweitzer hospital.

Some were suffering from gunshot wounds to the chest and head.

Local police commander Djalma Beltrame told Globo TV de Oliveira had left a letter at the scene indicating he wanted to kill himself.

But he said the note did not give a clear motive for the serial killing, the first of its kind in Brazil.

“It was a premeditated act,” Beltrame said. “He was clearly a hallucinating person."

He said the attack could have been far worse had a police patrol not driven past the school at the time and heard gunfire.

"If the police did not arrive as quickly as they did the tragedy could have been far worse, because this man had a lot of ammunition and was carrying two guns," he said.

Television pictures showed three helicopters landing on a football field next to the school and taking the young victims to hospital.

Frantic parents could also be seen crying and screaming outside the school as they awaited news that their children were alive and safe.

The school teaches about 300 children aged nine to 14 years.

Dorival Porto Rafael, a rubbish collector who was at the school at the time, told Globo online the gunman walked into a class where eighth-grade students were studying Portuguese.

"He came in saying he was going to give a talk... and without saying anything took out a pistol from his bag and started firing," Mr Rafael said.

Brazilian President Dilma Rousseff said she was "shocked and disturbed" at the attack. "Innocent children lost their lives and their future," she said.

Education minister Fernando Haddad described the shooting as "an unprecedented tragedy in Brazil."