Sandy Hook, Conn. — Connecticut State Police said Friday that 26 people, including 20 children, were killed in a shooting at a K-4 elementary school 60 miles northeast of New York City, and that the gunman was also dead, as well as another person at a home connected with the shooter.

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The gunman opened fire just after 9:30 a.m. inside Sandy Hook Elementary School in Newtown where his mother reportedly is a teacher. He blasted his way through the building as young students cowered helplessly in classrooms while their teachers and classmates were shot.

The attack comes less than two weeks before Christmas and appears to be the nation's second-deadliest school shooting, exceeded only by the Virginia Tech massacre in 2007.

The number of victims, the shooter’s identity and a possible second suspect were all the subject of active media speculation throughout the day Friday.

"This is an active, ongoing case, and there are many things that we won't and cannot discuss at this time," Lt. Paul Vance with the Connecticut State Police said Friday evening.

Vance would not identify the victims, he said, until they can be positively identified.

Eighteen children and six adults were dead at the crime scene, he said. Two other children were taken to a local hospital where they were pronounced dead. Another victim was injured.

Vance would not say who the shooter was or how he died.

Initially, multiple media outlets reported the gunman was Ryan Lanza, 24, of Hoboken, N.J., but later identified his younger brother, Adam Lanza, 20, as the shooter.

A report from a law enforcement official speaking anonymously mistakenly transposed the brothers' first names, according to The Associated Press.

Also in identifying the shooter, CBS News used a Facebook photo of a man named Ryan Lanza who is originally from Newtown. That man later removed his Facebook profile and told a New Jersey news organization that the shooter may have had his identification.

WRAL also used the photo, but has since removed it.

The AP also reported that Adam Lanza died from a self-inflicted gunshot wound and that his older brother, who is not believed to be involved in the shootings, told police that his brother was believed to have suffered from a personality disorder and was "somewhat autistic."

The younger Lanza lived with the mother, Nancy Lanza, in Connecticut. She is presumed to be dead.

'Evil visited this community today'

"Evil visited this community today and it's too early to speak of recovery, but each parent, each sibling, each member of the family has to understand that Connecticut — we're all in this together. We'll do whatever we can to overcome this event," Gov. Dannel Malloy said.

"They had their entire lives ahead of them," President Barack Obama said Friday afternoon from the White House briefing room.

Obama choked up at times and brushed away tears as he spoke, not as the president, he said, but as a parent. He ordered flags lowered to half-staff in mark of respect for the victims.

"Our hearts are broken today for the parents and grandparents and sisters and brothers of those little children and for the adults whose lives were lost."

Gov. Bev Perdue also ordered North Carolina flags lowered on state facilities until sunset Tuesday.

"Our thoughts and hearts are with the families of the victims of this senseless act," she said. "(We) are deeply shocked and heartbroken over this tragic loss of life."

The shootings instantly brought to mind episodes such as the Columbine High School massacre that killed 15 in 1999 and the July shootings at a movie theater in Aurora, Colo., that left 12 dead.

"You go to a movie theater in Aurora and all of a sudden your life is taken," Columbine principal Frank DeAngelis said. "You're at a shopping mall in Portland, Ore., and your life is taken. This morning, when parents kissed their kids goodbye knowing that they are going to be home to celebrate the holiday season coming up, you don't expect this to happen. I think as a society, we need to come together. It has to stop, these senseless deaths."

Questions remain about shooter, motive

Law enforcement officials, speaking on the condition of anonymity, said the gunman drove to the school in his mother's car. 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, the officials said.

Officials did not identify the person found dead in a Newtown home.

What is clear, from witnesses, is that the shooter had some kind of encounter with a school administrator in the school's main office.

Vance said the shooter then went to at least two classrooms in one section of the building.

Parents said their children heard arguing over the school's intercom system. One boy, a mother said, heard pops coming from speakers, which she presumed were gunshots. He said his teacher rushed him and his classmates out of the school.

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."

He said the shooter didn't utter a word.

Stephen Delgiadice said his 8-year-old daughter was in the school and heard two big bangs. Teachers told her to get in a corner, he said.

"It's alarming, especially in Newtown, Connecticut, which we always thought was the safest place in America," he said. His daughter was fine.

Mergim Bajraliu, 17, heard the gunshots echo from his home and ran to check on his 9-year-old sister at the school. He said his sister, who was fine, heard a scream come over the intercom at one point. He said teachers were shaking and crying as they came out of the building.

"Everyone was just traumatized," he said.

Mary Pendergast, who lives close to the school, said her 9-year-old nephew was in the school at the time of the shooting, but wasn't hurt after his music teacher helped him take cover in a closet.

Richard Wilford's 7-year-old son, Richie, is in the second grade at the school. His son told him that he heard a noise that "sounded like what he described as cans falling."

The boy told him a teacher went out to check on the noise, came back in, locked the door and had the kids huddle up in the corner until police arrived.

"There's no words," Wilford said. "It's sheer terror, a sense of imminent danger, to get to your child and be there to protect him."

"My heart goes out to them," he added, of the parents of the victims. "That’s an experience no parent should have to go through.”