This post has been moved up and will be updated as more information becomes available. Updates are by Paul Constant.
UPDATE: We'll be updating news as it comes in an afternoon post, in order to keep Slog loading times fast. [PC]
UPDATE 12:09 PM: John Boehner has ordered all the flags on Capitol Hill to be flown at half-mast. [PC]
UPDATE 11:51 AM: President Obama will speak in about twenty-five minutes, at 3:15 eastern time. [PC]
UPDATE 11:23 AM: The suspected shooter's name is being reported as Ryan Lanza, age
23 or 24. A reporter for NBC says a source tells him that the shooter's mother was a kindergarten teacher at the school. [PC]
UPDATE 11:12 AM: There are reports that "a parent of the suspected shooter has been found dead at a home in New Jersey." [PC]
UPDATE 11:08 AM: The death toll according to the Connecticut Post is now up to 29 dead, including 22 children. [PC]
UPDATE 10:58 AM: According to CNN, the other person being interviewed by authorities is not being called a suspect. [PC]
UPDATE 10:51 AM: President Obama will be speaking soon, according to NBC's Chuck Todd. [PC]
UPDATE 10:44 AM: They're giving a press briefing for basic information right now. The 911 call came after 9:30 am. Police arrived soon after. There were fatalities on the scene. The shooter is deceased inside the building, and police are now searching other sites related to the shooter. The school is now secure. President Obama has called "with condolences on behalf of the nation." More information will be released when the families are informed. [PC]
UPDATE 10:33 AM: Reuters is reporting that an entire classroom of students is unaccounted for. There will be a police briefing in an hour. [PC]
UPDATE 10:28 AM: Multiple outlets are reporting that the shooter is dead. CBS is reporting that a person of interest is in custody. Some reports indicate that this person in custody might be a second shooter, but those reports are unconfirmed by law enforcement. At mass shootings, there are frequently reports of multiple shooters; these scenes are chaotic and eyewitness testimony is often unreliable. As Megan noted, this Reuters page is a constantly updated source of information. [PC]
According the AP. Awful.