Nearly 20 people, including 10 children, died Friday in a shooting at a school in Newtown in the US state of Connecticut, CNN reported.
A parent who was inside the Sandy Hook Elementary School at the time of the attack said she heard what sounded like at least 100 rounds being fired.
She said she saw two school employees who had been shot dead.
Hospital officials in neighbouring Danbury told CNN they were treating three people wounded in the shooting. The victims were in "very serious" condition.
The shooter was dead, and his body was in a classroom at the school.
Police have recovered two weapons from the suspect, a Glock and a Sig Sauer. It was not clear if police killed the suspect.
The Hartford Courant newspaper said one victim had "numerous gunshot wounds".
Aerial images showed police officers armed with rifles following a dog into woods near the school.
Other officers, some in tactical gear, stood around the school with guns drawn.
A photograph showed teachers and police leading students out of the building across a parking lot.
One student, a third-grader, said she was sitting in her classroom when police flooded the area.
"We saw police officers and we heard them on our roof and in our building," the girl said.
Some of the children were crying, and others felt they had a stomachache, she said.
The girl's father told the station the incident was shocking. "I was pretty shaken up," he said.
The first phone calls came to police around 9.40 a.m.
Newtown officials told parents to stay by their phone and not to go to the school. But frantic parents converged at a fire station near the school after reports of the shooting, Xinhua reported citing the local WTNH-TV channel.
Following the firing, school children were evacuated to the firehouse and all schools in town were locked down.
One parent said the shooting took place during an administrators meeting, according to a report in the Danbury News Times.
BBC said Sandy Hook is a highly rated school with more than 600 students.