20 Children Among 27 Total Dead In Conn. Elementry School Shooting [UPDATED]

A shooting involving two gunmen erupted at a Connecticut elementary school this morning, prompting the town of Newtown to lock down all of its schools and draw SWAT teams to the school, authorities said today.

State Police confirm that one shooter is dead. A second gunman is apparently at large, sources told ABC News.

The shooting occurred at the Sandy Hook Elementary School in Newtown, about 12 miles east of Danbury.

State Police received the first 911 call at 9:41 a.m. and immediately began sending emergency units from the western part of the state. Initial 911 calls stated that multiple students were trapped in a classroom, possibly with a gunman, according to a Connecticut State Police source.

11:52 a.m.: Danbury Hospital confirms three patients have been taken there for treatment.

11:55 a.m.: Danbury Mayor Mark Boughton tells WABC three victims in hospital are in “very serious condition.”

12:09 p.m.: Sources tell ABC News multiple persons shot

12:11 p.m: LIVE streaming video from chopper above Sandy Hook Elementary.

12:19 p.m.: Federal agents are at the scene of the school with guns still drawn as parents rush to pick up their children.

12:24 p.m.: Law enforcement agents with weapons drawn seen running into wooded area behind the school.

12:26 p.m.: More than a dozen persons, including children shot and killed at Newtown, Conn., elementary school, federal, and state law enforcement sources tell ABC News.

12:36 p.m.: Law enforcement conducting car to car searches in area of school.

12:47 p.m.: More than 20 people, most of them young children, killed in elementary school shooting, according to law enforcement sources.

12:57 p.m.: Fatality numbers continue to rise. More than 25 people, mostly young children, killed in Newtown, Conn. school shooting, sources tell ABC News.

1:09 p.m.: Twenty-seven people, or more, most of them children killed in shooting, sources tell ABC News.

1:17 p.m: One shooter is described as 24-years-old, armed with four weapons and wearing a bullet-proof vest, sources tell ABC News.

1:26 p.m.: President Obama has been briefed on shooting by FBI director Bob Mueller and spoken with Conn Gov. Dan Malloy.

1:42 p.m.:” Shooter is deceased inside the [school,]” says Connecticut State Police spokesman Paul Vance.

1:44 p.m.: “The scene is secure. The public is not in danger,” says Connecticut State Police spokesman Paul Vance.

2:22 p.m.: Federal agents investigating whether slain Connecticut school gunman had a relationship with someone in the school, sources say.

2:28 p.m. The gunman in the Newtown, Conn., school shooting has been identified as Ryan Lanza, 24, of New Jersey. A dead body has also been found in his parents’ home, officials said. Lanza’s body was found in the school.

2:37 p.m.: Gunman Ryan Lanza’s mother found among the dead at Sandy Hook Elementary School.

2:46 p.m.: White House announces that President Obama will address the nation at 3:15 p.m.

2:48 p.m.: Hero teacher Kaitlin Roig tells ABC News that she barricaded her first grade students in classroom bathroom and locked the door when she first heard gun shots. “The kids were being so good. They asked: ‘Can we go see if anyone is out there? … I just want Christmas… I don’t want to die; I just want to have Christmas.’ I said, you’re going to have Christmas and Hanukkah… I tried to be positive.”

3:15: Gunman Ryan Lanza’s mother was a kindergarten teacher at the school. She and many of her students were found dead in the school.

3:15 p.m.: President Obama visibly emotional in remarks about Newton, Conn. school shooting.

3:17 p.m.: President Obama says majority of victims were students ages five to 10 years old.

3:18 p.m.: “As a country, we have been through this too many times,” President Obama says about shooting.

3:40 p.m.: 18 children pronounced dead at school; 2 dead at hospital; 6 adults dead at school, says Conn. State Police spokesman Paul Vance.

3:42 p.m.: Shooting took place in “one section of the school in two rooms,” says Vance, adds there is only one known shooter “right now.”

4:17 p.m.: Federal sources initially identified the suspect as Ryan Lanza, 24, of New Jersey, but there appears now to be confusion over the gunman’s identity.

4:18 p.m.: “My deepest sympathies are with families of those affected, and my determination to stop this madness is stronger than ever,” tweets New York City Mayor Michael Bloomberg, a staunch gun-control advocate.

4:41 p.m.: Federal law enforcement sources now say Connecticut school shooting gunman was Adam Lanza, 20, and not his brother Ryan Lanza, 24, as earlier reported. Adam was found dead in the school along with his mother, a kindergarten teacher there.

4:52 p.m: Ryan Lanza, 24, brother of gunman Adam Lanza, 20, tells authorities that his younger brother is autistic, or has Asperger syndrome and a “personality disorder.” Neighbors described the younger man to ABC as “odd” and displaying characteristics associated with obsessive-compulsive disorder.

Source: ABC.com