Blooded children exit school

Sandy Hook Elementary School teaches children from kindergarten through fourth grade - roughly ages 5 to 10.

"It was horrendous," said parent Brenda Lebinski, who rushed to the school where her daughter is in the third grade. "Everyone was in hysterics - parents, students. There were kids coming out of the school bloodied. I don't know if they were shot, but they were bloodied."

US President Barack Obama wipes a tear as he speaks about the shooting at Sandy Hook Elementary School in Newtown, Connecticut, during a press briefing at the White House in Washington Dec 14, 2012. [Photo/Agencies]

Television images showed police and ambulances at the scene, and parents rushing toward the school. Parents were seen reuniting with their children and taking them home.

"This is going to be bad," a state official told Reuters, requesting anonymity because the scope of the tragedy remained uncertain.  

Lebinski said a mother who was at the school during the shooting told her a "masked man" entered the principal's office and may have shot the principal. Lebinski, who is friends with the mother who was at the school, said the principal was "severely injured."

Lebinski's daughter's teacher "immediately locked the door to the classroom and put all the kids in the corner of the room."

Murphy has a friend with a daughter in Sandy Hook, and the daughter is OK. She did get an automated call from the school department this morning saying there was a "possible shooting" at the elementary school and that all schools were on lockdown.

Melissa Murphy, who lives near the school, monitored events on a police scanner.

"I kept hearing them call for the mass casualty kit and scream, 'Send everybody! Send everybody!'" Murphy said. "It doesn't seem like it can be really happening. I feel like I'm in shock."    

A girl interviewed by NBC Connecticut described hearing seven loud "booms" while she was in gym class. Other children began crying and teachers moved the students to a nearby office, she said.

"A police officer came in and told us to run outside and so we did," the unidentified girl said on camera.        

Newtown, with a population about 27,000, is in northern Fairfield County, about 45 miles (70 km) southwest of Hartford and 80 miles (130 km) northeast of New York City.

The United States has experienced a number of mass shooting rampages this year, most recently in Oregon, where a gunman opened fire at a shopping mall on Tuesday, killing two people and then himself.

The deadliest came in July at a midnight screening of a Batman film in Colorado that killed 12 people and wounded 58.

The Sandy Hook tragedy would be the deadliest elementary school shooting in US history.

The worst US high school shooting happened in 1999 when two students, Dylan Klebold and Eric Harris, went on a rampage at Columbine High School in Littleton, Colorado, killing 12 students and a teacher before turning their guns on themselves.

In 2007, 32 people were killed at Virginia Tech university in the deadliest act of gun violence in US history.    

In another notorious school shooting outside of the United States, in 1996 a gunman opened fire in an elementary school in Dunblane, Scotland, and killed 16 children and an adult before killing himself.