Almost a month after the massacre at an elementary school in the US state of Texas, more dramatic errors in the police operation are known.

At a hearing in the Texas Senate on Tuesday, Texas Public Safety Director Steven McCraw said just three minutes after the shooter entered a classroom and opened fire, nine police officers were outside the room, two of them with guns .

More were gradually added.

An 18-year-old gunman shot dead 19 children and 2 teachers at an elementary school in the small Texas town of Uvalde in late May.

The attacker shot the children and teachers in two connected classrooms with an assault rifle.

Classroom door not even locked

McCraw said the door to the classroom wasn't even locked as far as we know.

But none of the police officers present tried to simply open the door.

Instead, the operations manager waited for reinforcements, more guns and protective equipment - and for a key to the classroom "that was never used".

None of this was necessary, McCraw argued.

In such a situation, if in doubt, a police officer with a gun is enough to go in and stop the gunman - even if that poses a risk for the officer.

"Once you are there, it is your duty to intervene immediately and stop the shooter."

“Terrible decisions” and abject failures

The police officers outside the room had guns, protective gear and training for such situations, but the children had none, McCraw said.

Nevertheless, the students and teachers had to wait "an hour, 14 minutes and 8 seconds" for emergency services to enter the room to save them.

“That is intolerable.” The operations manager made “terrible decisions”.

He decided to put police officers' lives ahead of children's lives.

McCraw spoke of "miserable failure".

Shortly after the crime, it became known that various police officers were already in the hallway in front of the classroom at an early stage, but made no attempts to break into the room for a long time - although children from inside desperately called the police several times.

More than 75 minutes after the shooter opened fire, emergency services entered the room and killed the perpetrator.