NEWTOWN, Connecticut (AP) -- A gunman killed 26 people, including 20 young children, at a Connecticut school Friday morning in one of the worst school shootings in the country's history .
Frightened students who were rushed from the building by police were told to close their eyes.
The 20-year-old killer, carrying two handguns, committed suicide at the school, bringing the toll to 28, authorities said.
The rampage in the northeastern state of Connecticut was at least the fourth big shooting spree in five months in the United States. It was by far the deadliest of the year and most heart-wrenching.
The children were among the youngest victims of a mass shooting in recent history.
Frightened students who were rushed from the building by police were told to close their eyes. Children -- some crying, others looking frightened -- were escorted through a parking lot in a line, hands on each other's shoulders.
"Our hearts are broken today," President Barack Obama said, wiping his eyes during brief comments to reporters in one of the most emotional public moments of his presidency. The children killed were just 5 to 10 years old, he said. "They had their entire lives ahead of them -- birthdays, graduations, wedding, kids of their own."
The national debate over the issue of gun control in America exploded once again. Obama said the U.S. had been "through this too many times" with recent mass shootings and that the country has to come together to take meaningful action, "regardless of the politics." He did not give details.
Police shed no light on the motive for the attack. The gunman was believed to suffer from a personality disorder and lived with his mother in Connecticut, said a law enforcement official who was briefed on the investigation but was not authorized to publicly discuss it.
Law enforcement officials speaking on condition of anonymity said Adam Lanza killed his mother, Nancy Lanza, and then drove to the school in her car with three guns, including a high-powered rifle that he apparently left in the back.
Authorities said he shot up two classrooms but otherwise gave no details on how the attack unfolded.
The attack at Sandy Hook Elementary School, just two weeks before Christmas, was the nation's second-deadliest school shooting, exceeded only by the Virginia Tech university massacre in 2007 that left 32 dead.
This time, the victims were far smaller. Children told their parents they had heard bangs and, at one point, a scream over the intercom. Teachers ordered them to hide in closets or corners.
State police Lt. Paul Vance said 28 people in all were killed, including the gunman, and one person was injured.
Lanza's older brother, 24-year-old Ryan, of Hoboken, N.J., was being questioned, but a law enforcement official said he was not believed to have had any role in the rampage.
Investigators were searching his computers and phone records, but he told law enforcement he had not been in touch with his brother since about 2010.
The officials spoke on the condition of anonymity because they were not authorized to speak on the record about the unfolding investigation.
Adam Lanza and his mother lived in a well-to-do part of Newtown where neighbors are doctors or hold white-collar positions at companies such as General Electric, Pepsi and IBM.
At least three guns were found -- a Glock and a Sig Sauer, both pistols, inside the school, and a .223-caliber rifle in the back of a car, authorities said. A law enforcement official speaking on condition of anonymity said some of the guns used in the attack may have belonged to Lanza's mother, who had legally purchased five weapons.
The shooting shocked a tranquil community of 27,000 people in one of the wealthiest counties in the U.S., about 60 miles (96 kilometers) northeast of New York City.
On Friday afternoon, family members were led away from a firehouse that was being used as a staging area, some of them weeping. One man, wearing only a T-shirt without a jacket, put his arms around a woman as they walked down the middle of the street, oblivious to everything around them.
Another woman with tears rolling down her face walked by carrying a car seat with a young infant inside and a bag that appeared to have toys and stuffed animals.
Robert Licata said his 6-year-old son was in class when the gunman burst in and shot the teacher.
"That's when my son grabbed a bunch of his friends and ran out the door," he said. "He was very brave. He waited for his friends."
Licata said the shooter didn't say a word.
Stephen Delgiadice said his 8-year-old daughter heard two big bangs, and teachers told her to get in a corner. His daughter was fine.
"It's alarming, especially in Newtown, Connecticut, which we always thought was the safest place in America," he said.
Theodore Varga said he was in a meeting with other fourth-grade teachers when he