The gunman who killed 20 children and six adults at a school in Connecticut used a rifle as his main weapon, the chief medical examiner says.
All the victims at Sandy Hook school in Newtown died of gunshot wounds, H Wayne Carver II said.
A list of the dead has been released. All the children were aged six or seven, and all the adults were women.
The gunman, named in media reports as Adam Lanza, killed his mother before driving to the school and opening fire.
Head teacher Dawn Hochsprung is listed among the dead, along with adults Rachel DaVino, Anne Marie Murphy, Lauren Russo, Mary Sherlach and Victoria Soto.
The youngest child to be killed was Noah Pozner, who celebrated his sixth birthday only last month. Most of the children who died were girls and nearly all were aged six.
Dr Carver said all the victims had been hit more than once.
Initial reports suggested that the killer had used two handguns which he also had with him.
Earlier, Lt Paul Vance of Connecticut state police said the gunman had forced his way into the school, and had not been let in "voluntarily".
He said investigators had gathered "good evidence" in the search for a motive.
The gunman killed his mother at the home they shared before driving to the school in her car and opening fire. Reports say the guns used in the attacks were registered to her.
There are conflicting reports about whether she had worked at the school in the past.
Connecticut Governor Dannel Malloy made a television address saying the children were "taken from their families far too soon".
"What's important right now is love, courage and compassion," he said.
President Barack Obama has urged "meaningful action" against gun crime in the US in the wake of the attack.
"As a country we have been through this too many times," he said in an emotional White House address.
"We're going to have to come together and take meaningful action to prevent more tragedies like this, regardless of the politics."
Friday's killings took place in two rooms within a single section of the school, police have said. The shooting lasted just a few minutes.
As they heard the shots, teachers in other parts of the building tried to protect children by locking doors and ushering them into closets.
"I told them we had to be absolutely quiet, because I was just so afraid if he did come in, then he would hear us and just start shooting the door," said teacher Kaitlin Roig.
"I said to them, 'I need you to know that I love you all very much and that it's going to be okay', because I thought that was the last thing they were ever going to hear."
Library clerk Maryann Jacob described telling 18 children to crawl into a storage room, before barricading the door with a filing cabinet. "We set them up with paper and crayons," she said.
Dr Jeannie Pasacreta, a nurse practitioner and psychologist who has been advising parents on how to talk to their children, says neighbours have been cancelling Christmas parties and taking down decorations.
Early reports named 24-year-old Ryan Lanza, of Hoboken, New Jersey, as the gunman, but unnamed officials later said his brother Adam was the suspect.
Ryan Lanza was questioned by police, US media reported, but has not been named as a suspect.
In a separate development, police in Oklahoma have arrested a teenager for allegedly plotting to shoot and bomb students at his school in Bartlesville. Sammie Eaglebear Chavez, 18, is said to have tried to convince other students to help him carry out an attack.
The attack at Newtown is the second deadliest shooting attack at a US school or university.
In 2007, a student at Virginia Tech university killed 32 people and injured many more.
--Courtesy of BBC News