At least two children are dead and 17 people injured after a crazed gunman opened fire at a Catholic school church in Minneapolis early Wednesday — barricading the doors and unleashing hell as students were praying during a morning Mass.

The maniac — wielding a rifle, shotgun and pistol — approached the side of the Annunciation Catholic Church and started firing through the windows, striking the scores of children praying in the pews just before 8:30 a.m., police and officials said.  

Two kids, ages 8 and 10, were killed. In total, 17 people — including 14 kids — were injured, cops said.

A shooting has been reported at Annunciation Church and Catholic School in Minneapolis. FOX 9 Minneapolis-St. Paul

The lone gunman, identified by sources as Robin Westman, had put a wooden plank against some of the church’s side doors in an apparent attempt to trap the students and staff inside the sanctuary as he fired shots from all three guns. 

“This was a deliberate act of violence against innocent children and other people worshipping. The sheer cruelty and cowardice of firing into a church full of children is absolutely incomprehensible,” Minneapolis Police Chief Brian O’Hara said.

Officials seen at the scene of the shooting. FOX 9 Minneapolis-St. Paul

A woman cries at the scene of the shooting. FOX 9 Minneapolis-St. Paul

The gunman, who cops said was in his 20s, was later found dead from a self-inflicted gunshot wound.

Of the injured, two children were in a critical condition, police said.

Fifth grade Annunciation student Weston Halsne told NBC News his friend Victor was shot while attempting to shield him from bullets during the Mass. The young survivor said he hid under a pew when the shooting started — just as he’d learned in active shooter drills at the school.

At least six children were being treated at Children’s Minnesota — a pediatric trauma hospital, according to officials. Hennepin Healthcare, which has Minnesota’s largest emergency department, said it had received 11 patients.

Here is the latest on the active shooting reported at Minneapolis Catholic school

“These were Minneapolis families. These were American families. And the amount of pain that they are suffering right now is extraordinary,” an emotional Mayor Jacob Frey said.

“Don’t just say this is about thoughts and prayers right now. These kids were literally praying. It was the first week of school. They were in a church,” he continued.

“They should be able to go to school or church in peace without the fear of violence.”

Authorities haven’t yet determined a motive for the bloodshed but investigators are currently reviewing an apparent manifesto and videos that detail, in part, the gunman’s psychotic obsession with mass shooters.

A sick 20-minute video posted on YouTube before the shooting showed a hand turning pages of a red notebook laid out on top of what appears to be schematic gun diagrams.

Other videos show an obsession with mass shooters — including Sandy Hook killer Adam Lanza.

Officials have said the shooter did not have a known extensive criminal history.

The school, which is located next door to the church, is for kindergarten through eighth-graders.

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Students, who had only just returned to class on Monday, were attending an all-school Mass at the time.

Scores of local and state police, federal Bureau of Alcohol, Tobacco and Firearms agents and other authorities descended on the scene after the shooting broke out.

Officials stand at the entrance to the building. FOX 9 Minneapolis-St. Paul

People react at the scene as officials arrive. FOX 9 Minneapolis-St. Paul

Bill Bienemann, who lives just a few blocks away and has long attended Mass at Annunciation Church, recalled hearing dozens of shots over several minutes.

“I was shocked. I said, ‘There’s no way that could be gunfire,’” he said. “There was so much of it. It was sporadic.”

A reunification zone was set up near the school, while others were being urged to stay away “to allow emergency personnel to help victims.”

Parents could be seen escorting students for the school in the aftermath.

President Trump and Minnesota Gov. Tim Walz were among those briefed on the shooting early on.

“Please join me in praying for everyone involved!” Trump said on social media.

In his own post, Walz said: “I’m praying for our kids and teachers whose first week of school was marred by this horrific act of violence.”

The shooting was just the latest in a series of fatal shootings in the city in less than 24 hours.

One person was killed and six others were hurt in a shooting Tuesday afternoon outside a high school in Minneapolis.

Hours later, two people died in two other shootings in the city.

The church shooting, though, didn’t appear to be related to the others, the police chief said.

With Post wires