"Child is advising he is in the room, full of victims," the dispatcher can be heard saying in the video. "Full of victims at this moment."
"Is anybody inside of the building at this...?" the dispatcher asked.
Minutes later, the dispatcher says again: "Eight to nine children."
MORE: Justice Department to review law enforcement's response to Uvalde school shooting
The video, obtained by ABC News, also shows police rescuing children from inside the school by breaking through a window and pulling them out, and also leading them out the back door to safety.
Early on, an officer can be heard warning bystanders to stay back because there is a man with a rifle.
Minutes later, what appear to be gunshots are heard ringing out.
The video, which appears to show some of what took place outside the school, raises new questions about law enforcement's response to one of the nation's deadliest school shootings, which left 19 children and two teachers dead.
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The gunman was left inside the classroom for 77 minutes as 19 officers waited in the hallway -- and many more waited outside the building -- after the incident commander wrongly believed the situation had transitioned from an active shooter to a barricaded subject, law enforcement has said.
Federal officers ultimately decided to enter the building and killed the gunman, according to law enforcement sources.
At a news conference Friday, Texas Department of Public Safety Director Steven McGraw said children inside the classroom had called 911 a number of times begging for them to "please send police now." It appeared that information may not have been relayed to officers on the ground, he said.
"That question will be answered," McGraw said when asked directly if the incident commander on the ground received the 911 information. "I'm not going to share the information we have right now. Because I don't have -- I don't have the detailed interview right now."
WATCH: Official says police made 'wrong decision' not to enter classroom during Uvalde school shooting
But the video obtained by ABC News, taken just outside the premises, appears to show that 911 dispatchers were relaying the information -- including information that the room was "full of victims." It is not clear who on scene, if anyone, heard the calls coming in from the dispatchers.
"Advise we do have a child on the line," an apparent dispatcher can be heard saying in the video.
The dispatcher's information heard on the video appears to match the readout of the 911 calls provided last week by law enforcement officials. McGraw said a child had called 911 saying she was in room 112 and had "advised there were multiple dead."
WATCH: 9-year-old says teacher played dead after being shot in Uvalde classroom, recounts seeing gunman
Later, McGraw said, "she called back and said there's eight to nine students alive."
More than one of the children who dialed 911 from inside the classroom survived, McGraw said on Friday.
The Department of Justice on Sunday announced it would be conducting a "fair, transparent, and independent" review of the law enforcement response to the shooting. The findings of the review, the department said, would be published in a report and made available to the public.
"The goal of the review is to provide an independent account of law enforcement actions and responses that day, and to identify lessons learned and best practices to help first responders prepare for and respond to active shooter events," DOJ said in its release.
SEE ALSO: US sees sharp rise in deadly mass shootings
Since 2017, mass shootings in the United States -- described as shooting incidents in which at least four people are injured or killed -- have nearly doubled year over year. Already, there have been 212 mass shooting incidents in 2022 -- a 50% increase from 141 shootings in May 2017. The graphic above shows the number of shooting incidents per state. Mobile users: Click here to see our map of mass shootings in the US from the last five years
The number of people injured or killed does not include the suspect or perpetrator. These graphics show the number of victims across all mass shootings from the last five years.