Gunshots boomed in the background as panicked callers flooded Newtown’s 911 emergency line with desperate pleas for help as deranged gunman Adam Lanza blasted his way into Sandy Hook Elementary School and massacred 26 students and staffers, recordings released Wednesday reveal.

“Sandy Hook School, I think there’s someone shooting in here, Sandy Hook School!” a terrified woman reported in one of the earliest of seven calls released by police.

“I caught a glimpse of somebody. They’re running down the hallway. Oh, they’re still running and still shooting. Sandy Hook school, please,” the woman pleaded, her voice trembling.

Another call came from a custodian, Rick Thorne, who said that a window at the front of the school was shattered and that he kept hearing shooting.

Thorne remained on the phone for several minutes.

“There’s still shooting going on, please!” the custodian pleaded to the 911 dispatcher, as six or seven shots could be heard booming in the background. “I keep hearing shooting, I keep hearing popping! … Still, it’s still going on!”

Warning: Audio may be disturbing for some listeners

While on the line with Thorne, the dispatcher told somebody off the call: “Get everyone you can going down there.”

The recordings show dispatchers calmly responding to the panicked janitor, a teacher and others while assuring them help was on the way as gunman Adam Lanza blasted his way through the school.

The operators urge the callers – who reported hearing multiple gunshots – to take cover as they desperately contact town and state police for help.

The operators also ask about the welfare of the children.

Lanza, 20, stormed the school on the morning of Dec. 14 and gunned down 20 children and six educators with a semi-automatic rifle. He had earlier killed his mother nancy as she slept, and blew his own brains out as police arrived.

The calls begin at 9:35 a.m. from the school’s central office, saying the front glass had been shot out.

There were a total of seven landline calls from inside the school to Newtown police — including Thorne’s.

The janitor stayed on the phone with a dispatcher as he made his way through the school trying to warn staffers and students about Lanza’s bloody rampage.

Another call came from a teacher.

“It sounds like there are gunshots in the hallway. I’m a teacher at the school,” the woman said. “All of my students are in the classroom …the door’s not locked yet.”

The dispatcher tells her to lock the door and keep the children away from the windows.

Many parents of the young victims opposed their release.

Neil Heslin, whose 6-year-old son Jesse Lewis was killed, passed up a chance to hear the tapes himself and said the release makes it hard for families to find closure.

“I haven’t listened to them or read a transcript. I understand the Freedom of Information act and the legality of it, but I kind of wish or would have hoped that they could have prevented them from being released,” Heslin told The Post.

“It’s a constant reminder of the tragedy that happened on Dec. 14. To hear over and over again what happened, it opens a wound up and keeps it open. It’s a hard thing to get any bit of closure with. It’s something we all wish we could forget.”

Nicole Hockley, whose son Dylan was also among the 20 first-graders killed, did not want the calls to be made public.

“What parent could possibly want that,” Hockley told ABC News. “It serves no public good, it’s not in anybody’s interest. It’s not the way I want Dylan to be remembered.”

The recordings were released after a lengthy fight before Connecticut’s Freedom of Information Commission and just days after a state prosecutor dropped his fight to continue withholding them.

The recordings were scheduled to be released on the Newtown Police Department’s Web site, but police officials canned that plan about noon on Wednesday without explanation.

Instead, they were to be released on CDs by a law firm representing the town.

Other 911 calls that were made from cellphones and routed to state police dispatchers in Litchfield, Conn., were not among the tapes released.

Those include calls from a woman who was injured in the foot and a parent who called from inside a conference room during the shooting, according to documents released last week by prosecutors.

The calls are the subject of a separate, pending FOI request.

The prosecutor in charge of the Newtown probe, State’s Attorney Stephen Sedensky III, had argued that releasing the tapes could hurt the investigation, subject witnesses to harassment and violate survivors who deserve special protection as victims of child abuse.

A state Superior Court judge dismissed those arguments last week, declining to keep the tapes sealed while Sedensky pursued an appeal of the FOI commission’s order.

Sedensky said Monday that he would not pursue the case further.

Anticipating the release, Newtown’s interim Schools Superintendent John Reed sent a letter to parents and staff Tuesday warning them of the release.

“I want you to have the opportunity to think about what steps, if any, you may wish to take to minimize media exposure for you and your family. I expect significant media coverage through Thursday,” Reed wrote.

“Like you, I have not listened to the tapes but I suspect for many persons the tapes will be an emotional trigger. I remain confident that by supporting one another with love and understanding we will continue to move forward as a school system and community.”

Reed also encouraged parents to talk to school counselors, psychologists social worker about any concerns they have for their children’s emotional health.

Newtown First Selectman Pat Llodra recently said she supported releasing the tapes to stop the steady stream of media leaks in the case.