According to police, the shooter was 24-year-old Ryan Lanza. Among those killed was his mother, who worked at the school. Before leaving home Lanza shot his Father, as well.
The shooter himself was gunned down by the police arriving on the scene.
Reports say the attacker was armed with two handguns.
All schools and daycare centers of the city are closed.
27 dead, including children, in Connecticut shooting
A gunman bursting into an elementary school in Newtown, Connecticut, has killed 27, including 18 children, and wounded at least three people.
One of the wounded people is a teacher. He is now in hospital with a leg wound.
Arriving police officers shot dead the attacker.
Reports say he was armed with two handguns and might have had an accomplice.
All Newtown schools and daycare centers are shut.
Gunman killed in Connecticut shooting - official
The suspected gunman in Friday's shooting at a Connecticut elementary school is dead on the scene, a source with knowledge of the investigation told.
The source also said police have recovered two weapons from the suspect, a Glock and a Sig Sauer. It's unclear if police killed the suspect, the source said.
School shooting in Connecticut, 1 child reportedly dead
One child is reported dead after a gunman opened fire at a Newtown, Connecticut elementary school Friday morning.
The Hartford Courant confirmed just after 11 a.m. that one student has been killed following an incident that began earlier in the morning, citing reports from authorities on the scene.
Moments earlier, authorities confirmed that a suspected gunman was also dead while at least three others were transported to a nearby hospital.
Police are considering the possibility of second shooter and are now searching for a purple automobile that was seen heading out of the city.
Shots were fired at around 9:40 a.m. this morning inside the main office at Sandy Hook Elementary School, where normally around 600 students in grades kindergarten through four attend class.
The school has since been flanked by dozens of #mce_temp_url#state troopers, who are assisting local officers dispatched to the scene.
All public and private schools in Newtown, CT have been placed on lockdown following orders from the superintendent, and the police are on the scene now attempting to determine the extent of the incident.
The Newton Bee is reporting multiple injuries, and a hospital in nearby Danbury, CT says they have received three patients from the school.
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