Police say the shooter in Friday's mass killing at northeastern U.S. elementary school forced his way into the building before gunning down 20 young children and six adults.

Police Lieutenant Paul Vance told reporters Saturday that 20-year-old Adam Lanza was not voluntarily let into Sandy Hook Elementary School in Newtown, Connecticut on Friday. He did not elaborate on how Lanza forced his way in, saying the investigation is ongoing.

Vance also said the victims of the shooting have been positively identified and promised a medical examiner and the superintendent of schools would speak to reporters later on. He said the one shooting victim who survived is “doing fine” and will be instrumental to the shooting investigation.

U.S. authorities have yet to say what might have been the gunman's motives in the shooting, which took place in a small community 130 kilometers northeast of New York City.

A VOA reporter on the scene said news outlets from Japan, China, Sweden and other countries have sent reporters to cover the event, one of the largest mass shootings in recent U.S. history.

Hundreds of mourners descended on a church in Newtown Friday night to grieve the deaths, as the community and the nation sought to absorb the scope of the tragedy. Governor Dannel Malloy told the mourners “evil visited this community today.”

On Saturday, U.S. President Barack Obama said in his weekly address that every parent in America has “a heart heavy with hurt.” He called for “meaningful action” to prevent more tragedies.

Witnesses say the gunman dressed in black military fatigues entered the school at mid-morning Friday, opening fire on children and their teachers in two rooms. The principal of the school was among those killed.

Officials say the shooter died at the scene of a self-inflicted gunshot. Two semi-automatic handguns were found nearby. A military assault rifle was later found in the gunman's car.

Authorities say the shooter killed his mother at her home where he also lived, then drove her car to the school where witnesses say he opened fire without saying a word.

The gunman's brother was taken by police for questioning late Friday in New Jersey. Police say he is cooperating in the probe.

Video from the crime scene showed children being rushed from the school single file, people hugging, and frantic parents either waiting for word on their children or hugging them once found. It took several hours before the full scope of the tragedy became public.

The usual Republican Party address Saturday was not delivered. Republican leaders said this was a time for the president to speak for the nation.