Twenty-seven people, including 18 children, have been killed in a shooting at Sandy Hook Elementary School, according to the Associated Press.
The report cites an official with knowledge of the situation.
Sources told The Courant that there are at least 20 shooting victims. Many of the shootings took place in a kindergarten classroom, sources said.
One entire classroom is unaccounted for, sources said.
The shooter -- identified by CNN as Ryan Lanza -- is dead, and the situation is secure, said State Police Lt. J. Paul Vance.
Another official, speaking on condition of anonymity because the investigation was still under way, said the gunman apparently had two guns.
A law enforcement official in Washington said the attacker was a 20-year-old man with ties to the school and that one of the guns was a .223-caliber rifle.
Meanwhile, police are searching residences in Newtown and in Hoboken, N.J., associated with Lanza, sources say.
Three people were brought to Danbury Hospital, but their condition is unknown. The emergency room is on lockdown.
Shortly after 9:40 a.m., police reported that a shooter was in the main office of the school. A person in one room had “numerous gunshot wounds,” police said.
Groups of students — some crying, some holding hands — were being escorted away from the school by their teachers. Some students were still in the school at 10:30 a.m., parents said.
Police were still searching the school at 11 a.m., and police dogs were brought in. Around noon, the triage area was broken down, stretchers were taken away and the SWAT team left the building.
School and local emergency officials were accounting for the children, who were released to their parents. Some parents were sequestered at the Sandy Hook fire department, directly in front of the school.
Other frustrated parents were desperately trying to get information from officials as they searched the school.
Vanessa Bajraliu, a 9-year-old fourth grader, heard the shots.
"I saw policemen -- lots of policemen in the hallway with guns," she said. "The police took us out of the school. We were told to hold each others' hands and to close our eyes. We opened our eyes when we were outside."
Her brother, 17-year-old Mergim Bajraliu, a senior at Newtown High School, was at his nearby home when he heard shots, he said. He first went to a neighbor's house.
"Then we heard sirens," he said.
He rushed to the school on foot and saw a girl being carried out, he said. She looked badly injured. Another girl had blood on her face, he said.
Mergim soon found his sister and took her away from the scene.