New footage has been released that shows how a deadly shooting in a Texas school unfolded.

Nineteen children and two teachers were killed when Salvador Ramos targeted Robb Elementary School in Uvalde.

The video shows the 18-year-old gunman crashing his pickup truck and entering the building -carrying an AR-15 assault rifle and walking down a hallway unhindered at 11.33am on 24 May.

Moments later, a child is seen coming around the corner of the hallway, and running away.

Police officers first arrive two-and-a-half minutes later. Two approach the classroom, but retreat after shots are fired.

At 11.52am, more policemen arrive – armed with guns, wearing body armour and carrying ballistic shields, but they are seen milling in the hallway.

At 12.30pm, another officer is seen stopping to get hand sanitiser.

At 12.50pm – 77 minutes after the gunman entered in the school – officers breach the classroom and kill him.

The footage was recorded from hallway CCTV within the school, and portions have been published by the Austin American-Statesman newspaper and KVUE.

Delays in the law enforcement’s response have been the focus of federal, state and local investigations into the massacre and its aftermath.

Families of the victims have been campaigning for the footage to be released, and are due to view the full recording this weekend.

The result of an investigation by the Texas state legislature is also set to be published.

Residents in Uvalde have been angered by what the footage shows, and at a council meeting on Tuesday night, they shouted for action and demanded police face consequences.

Earlier this month, a report by the Texas Department of Public Safety found that an Uvalde police officer could have shot Ramos before he entered the school, but hesitated while he waited for permission from a supervisor.

In a statement, that department’s director, Steve McCraw, said the video provides “horrifying evidence” that the law enforcement response was a failure.

However, he said the families of those killed should have had the chance to have seen the footage first, and he was “deeply disappointed” by the newspaper’s decision to publish the video.

Brett Cross, whose 10-year-old son Uziyah Garcia died in the shooting, said: “We’re tired of seeing things after the media gets a hold of them. Nobody is telling us anything. And it’s disrespectful to not just us, but our kids’ memories.”