U.S. President Barack Obama says he and parents across the country are feeling overwhelming grief over the mass school shooting Friday that killed children and school staff in the northeastern state of Connecticut.

Mr. Obama, visibly upset and wiping tears from his eye as he spoke at the White House, said most of the victims were children who had their whole lives in front of them.

A state police lieutenant told reporters that 20 children and six adults were killed at the Sandy Hook Elementary School in Newtown, Connecticut. He said the gunman was also dead.

The president called the shooting a “heinous crime.” He said the country has endured too many of these tragedies in the past few years and will have to come together and take meaningful action to prevent another such incident.

In a proclamation, the president ordered flags at the White House and other government buildings to be flown at half-staff until Tuesday.

Governor Dannel Malloy called the shooting a tragedy of unspeakable terms.

News report says the suspected gunman is a man in his 20s named Ryan Lanza. Reports say his mother, who worked at the school, was killed in the attack.

Mr. Obama said he spoke with the governor to express his sadness, and pledged help with federal resources.

Images from the scene showed children being rushed out of the school, people hugging and parents with their children. It took several hours before the full scope of the tragedy became public.