What an unspeakably horrific thing happened in Newtown, Connecticut today. How does one speak about a horror on the scale of this one? As a resident of Connecticut, as a human, I am appalled and shocked. Can't begin to imagine the pain, the shattered hearts of the bereaved families. "As many as 27 people have been killed, including many children, in a shooting attack at a primary school in the US state of Connecticut, US media say.
At least 18 children are among the dead at Sandy Hook Elementary School in Newtown, the Associated Press reported.
State police spokesman Paul Vance said the gunman died at the scene - but would not confirm the number of deaths.
If confirmed, Newtown would be the second-deadliest US shooting, after 32 people died at Virginia Tech in 2007.
Friday's shooting is the third major shooting in the US in 2012.
In July an attack that killed 12 people at a premiere of a Batman film in Aurora, Colorado. In August six people died at a Sikh temple in Wisconsin. Children's 'eyes covered'
Governor Dannel Malloy is meeting the families of the victims, a spokesman said, and is expected to visit the school later in the day. He is expected to make a statement later on Friday.
White House Press Secretary Jay Carney told reporters that US President Barack Obama had been informed of the incident and was receiving regular updates.
Sandy Hook School - described by correspondents as a highly rated school has more than 600 students in classes from Kindergarten to 4th Grade - spanning the ages five to 10.
Police arrived at the school soon after 09:40 local time (14:40 GMT), answering reports that a gunman was in the school's main office and one person had "numerous gunshot wounds".
Scores of officers at the scene carried out a full search of the site. Classes were cancelled as the situation developed.
Schools across the district were immediately on lock-down as a preventive measure, officials said.
US TV networks identified the gunman as Ryan Lanza, 24, reported to be from New Jersey. According to reports, his mother was a teacher found among the dead at the school.
He was described as a man in his 20s, dressed in black, with links to the school, a law enforcement official told the Associated Press.
The official said the gunman used a .223-calibre rifle during the attack, adding that police in the state of New Jersey are investigating a location there in connection to the shooting.
With the death toll rising, it emerged that one entire classroom of students may remain unaccounted for, local sources reported.
Three other people were taken to hospital and are reported to be in "very serious condition", Danbury Mayor Mark Boughton told CNN.
One witness speaking to CNN said that shots were heard coming from the hall. There "must have been 100 rounds" fired, she told the channel.
Local media have reported that firefighters instructed children to close their eyes and run past the school's office as they exited the building.
Other sources suggest that some of the shots were fired in a school classroom.
There were early unconfirmed reports of two shooters, but no further details of a second gunman mentioned by police.
May the innocent souls, young and old, find peace with God.