People screamed ‘Go in there! Go in there!’ at officers, say witnesses (Picture: Getty Images)

A heartbroken father who lost his daughter in the Texas school massacre says he wanted to charge into the building himself after police allegedly ‘weren’t doing anything like they are supposed to’.

Officials have acknowledged that gunman Salvador Ramos, 18, was inside for up to an hour and killed 19 children and two teachers before a tactical team shot him dead.

Witnesses have accused ‘unprepared’ cops of not acting fast enough, while Border Patrol agents reportedly couldn’t open the classroom door and had to get a staff member to find a key, according to one law enforcement source.

But police say the gunman was barricaded inside the classroom for at least 30 minutes and they engaged ‘immediately’.

Women screamed ‘Go in there! Go in there!’ at officers when the attack began, said witness Juan Carranza, 24.

The local, who saw the scene from outside his house, across the street from Robb Elementary School, says officers did not move.

Claiming they should have gone in sooner, he said: ‘There were more of them. There was just one of him.’

Javier Cazares, whose fourth-grade daughter, Jacklyn Cazares, lost her life, said he rushed to the scene as soon as he heard the terrifying news to find police still gathered outside.

Distressed that no action had been taken, he asked bystanders if they’d go into the school with him.

It is America’s deadliest school shooting since 20 children and six adults died at Sandy Hook Elementary in Newtown, Connecticut, in 2012 (Picture: Reuters)

Nineteen young children and two adults had their lives ripped away from them (Picture: Anadolu Agency via Getty Images)

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‘Let’s just rush in because the cops aren’t doing anything like they are supposed to’, he said. ‘More could have been done. They were unprepared.’

Ramos had shot his grandmother, before crashing his car into a ditch outside the school and shooting at two people outside a nearby funeral home, who ran away uninjured.

He is said to have ‘encountered’ a school district security officer before entering, although there are conflicting reports from authorities on whether the two exchanged gunfire.

After running inside, he opened fire on two officers from the Uvalde Police Department outdoors who were injured, said Texas Department of Public Safety spokesperson Travis Considine.

The teenager then stormed into a classroom, barricaded victims inside and started shooting with his AR-15-style semi-automatic rifle. All of those killed were in the same classroom.

Christopher Olivarez of the Department of Public Safety said: ‘It just shows you the complete evil of the shooter.’

Forty minutes to an hour elapsed from when Ramos attacked the school security officer to when he himself was shot, Department of Public Safety director Steve McCraw said.

But a department spokesman said later that they could not give a solid estimate of how long the gunman was in the school or when he died.

‘The bottom line is law enforcement was there’, Mr McCraw said. ‘They did engage immediately. They did contain (Ramos) in the classroom.’

Citing a briefing he was given, Rep. Tony Gonzales, whose district includes Uvalde, said other children were able to leave the school as the shooter stayed inside the classroom after killing 21 people.

‘And then (the shooting) stops, and he barricades himself in. That’s where there’s kind of a lull in the action’, he told CNN.

Two family members comfort each other during a prayer vigil on Wednesday evening (Picture: AP)

A woman holds a photo of Nevaeh Bravo, who was killed in the mass shooting (Picture: AFP via Getty Images)

The Texas gunman has been identified as Salvador Ramos, 18, who was shot to death by a Border Patrol agent (Picture: Police Handout/ZUMA Press Wire Service/Shutterstock)

‘All of it, I understand, lasted about an hour, but this is where there’s kind of a 30-minute lull. They feel as if they’ve got him barricaded in. The rest of the students in the school are now leaving.’

Raul Ortiz, Chief of the US Border Patrol, said members of the Border Patrol tactical team, a search and rescue responder and a few other agents joined local officers to form a team that went after the gunman.

‘They didn’t hesitate. They came up with a plan. They entered that classroom and they took care of the situation as quickly as they possibly could’, he said.

The Uvalde Police Department has been contacted for comment.

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