[Updated at 1:45 p.m. ET] We are now learning that a male is being questioned by investigators, but he is not being called a suspect, CNN's Susan Candiotti reports.
[Updated at 1:42 p.m. ET] Connecticut State Police Lt. Paul Vance said the shooter is dead inside the school.
Vance said there are a number of fatalities that includes both children and adults. He did not add more details about how many people were killed during the school shooting.
[Updated at 1:41 p.m. ET] Police have now begun their briefing on the shooting.
[Updated at 1:32 p.m. ET] We're hearing more from the scene of the massacre through tweets and interviews.
[Updated at 1:23 p.m. ET] President Obama has spoken to FBI Director Robert Mueller and Connecticut Gov. Dan Malloy to get the latest information and express his condolences, White House spokesman Jay Carney said.
[Updated at 1:21 p.m. ET] We're now hearing that it may be a while for the briefing from the police.
[Updated at 1:17 p.m. ET] This was the scene from the air earlier, taken by News 12 Connecticut, with emergency vehicles in the school parking lot