18.10 (13.10) A parent at the school, who was there this morning for a meeting, has described how she heard the "pop-pop" of gunfire in the hallway. Three people went out into the hall and the woman said only one - the vice principle - came back. The vice principle was reportedly wounded as she crawled back in. The woman described hearing shouting in the hall but it was not clear whether it was the shooter or responding police.
18.08 (13.08) The gunman was found dead inside a classroom but it's not clear whether they killed themselves or were killed by police. Initial reports suggested there were two shooters, but it's not clear whether that is the case.
18.05 (13.05) Authorities in Newtown are about to hold a press conference, where we will get our first official briefing on the tragedy that unfolded this morning.
18.01 (13.01) The school is only kindergarten through fourth grade, meaning the oldest children are 10 years old. There are 600 kids at the school.
17.59 (12.59)The scene outside Sandy Hook Elementary School is now an all too familiar one in modern America: swarms of police cars in the car park, heavily-armed officers from the SWAT team patrolling the area and new helicopters circling overhead.
17.56 (12.56) There are reports than an entire class - a room full of young children - are unaccounted for.
17.55 (12.55) CNN is now reporting "close to 20" dead at the school, of which at least 10 are children.
17.53 (12.53) If that CBS figure of 27 dead is confirmed, and so far there has been no official confirmation, this will be the worst school massacre in the history of the United States - far outstripping Columbine in 1999 which left 13 victims dead.
17.48 (12.48) Jay Carney, the White House spokesman, says the President was informed at 10.30am and will receive regular updates throughout the day. The FBI and other law enforcement agencies are involved.
17.45 (12.45)Two 9mm handguns have been recovered from the scene and police have taped off a black car in the car park outside the school.
17.44 (12.44) We're now getting reports of 27 people, including 14 children, killed at the school. There's no confirmation of that but it is an extraordinary tragedy if true.
17.41 (12.41) The shooting was reported at 9.40am EST, around three hours ago, and the situation remains very unclear. The best information we have so far is that two members of school staff are dead along with a shooter. Witnesses claim "at least 100 rounds" were fired during the incident.
17.40 (12.40) Police are responding to a shooting at Sandy Hook Elementary School in Newtown, Connecticut, where so far three people are reported to have been killed.
