Two young children were fatally shot and 17 others wounded, including 14 children, in a brazen attack on a Catholic school in south Minneapolis Wednesday morning, authorities said, as a gunman armed with multiple weapons fired through church windows during a student mass marking the start of the school year.

The shooting unfolded just before 8:30 a.m. at Annunciation Catholic School, where students from preschool through eighth grade had gathered for their first children's Mass of the new academic year, which began Monday.

Police said the assailant, a man in his early 20s with no known criminal history, approached the building from outside and unleashed gunfire into the pews, striking worshippers inside.

He was armed with a rifle, a shotgun and a pistol, and a smoke bomb was later found at the scene.

Minneapolis Police Chief Brian O’Hara, addressing reporters at a press conference, described the horror: "During the mass, the gunman approached on the outside, on the side of the building, and began firing a rifle through the church windows towards the children sitting in the pews at the mass. Shooting through the windows, he struck children and worshipers that were inside the building."

O’Hara confirmed the two slain victims were an 8-year-old and a 10-year-old, both killed in the pews.

"Their parents have been notified. Seventeen other people were injured, 14 of them children. Two of those children are in critical condition. The coward who fired these shots ultimately took his own life," he said."The sheer cruelty and cowardice of firing into a church full of children is absolutely incomprehensible," O’Hara added. "This was a deliberate act of violence against innocent children and other people worshiping."

The gunman was found dead inside the church from what police believe was a self-inflicted gunshot wound.

Dozens of children were present during the service, which typically lasts about 30 minutes and starts at 8:15 a.m.

The first emergency call came in at 8:27 a.m., with reports of a man dressed in all black and armed with a rifle.

When officers arrived, they immediately began administering first aid and rescuing children hiding throughout the building.Investigators are searching a vehicle left behind by the shooter for clues to a motive, O’Hara said, noting the probe is in its early stages.

The school, which enrolls about 370 students and recently celebrated its church's 100th anniversary, had no unusual incidents or police visits in the days leading up to the attack, according to Helen Corkran, the school's director of pastoral care.

"It’s a good school. There are wonderful people there," Corkran said. "It was the first children’s mass of the new school year."

Minneapolis Mayor Jacob Frey, speaking at the same press conference, delivered an emotional plea.

"Children are dead. There are families that have a deceased child. You can not put into words the gravity, the tragedy, or the pain of this situation... Those families are suffering immense pain right now. Think of this as if it’s your own."

"Don’t just say this is about thoughts and prayers right now," Frey continued. "These kids were literally praying. It was the first week of school. Every one of us needs to be wrapping our arms around these families giving them every ounce that we muster. These were Minneapolis families. These were American families."

"This also is not about thoughts and prayers right now. These kids were literally praying. They were in a church. These are kids who should be learning with their friends. They should be playing on the playground," Frey added.

First responders reported up to 20 victims in emergency dispatch audio, with a massive law enforcement response converging on the area around West 54th Street between Lyndale and Nicollet avenues.

The city's official X account declared by 10:29 a.m. ET that there was "no active threat to the community at this time," urging residents to stay away: "The shooter is contained. Stay away from the area to allow emergency personnel to help victims – W. 54th Street between Lyndale and Nicollet Ave."

Children’s Minnesota hospital confirmed it was treating five children but declined to provide further details "to respect the privacy of our patients and families."

Nearby residents described hearing lengthy gunfire that sounded like a gunfight involving multiple shooters.

Diamond Lake neighbors Mary Faist and Benny Pekala, who witnessed families reuniting at Mount Olivet, recounted the chaos: "I don’t know why they (mass shooters) do it. If you have a problem with religion, resolve it a different way. Seeing little kids walk out, some of them have a lot of blood down their shirts."

An unnamed witness told CNN the gunfire continued for several minutes.

The incident marks the fourth shooting in Minneapolis within 24 hours, following three separate shootings from Tuesday into Wednesday that left three people dead and at least eight others wounded.

Minnesota Gov. Tim Walz said he had been briefed and that state agencies were assisting: "The [Bureau of Criminal Apprehension] and State Patrol are on scene. I’m praying for our kids and teachers whose first week of school was marred by this horrific act of violence."

Walz also spoke by phone with President Donald Trump about the shooting.U.S. Secretary of Homeland Security Kristi Noem posted on X: "We are in communication with our interagency partners, and will share more information as soon as it becomes available. I am praying for the victims of this heinous attack and their families."

President Trump, on Truth Social, stated: "I’m been fully briefed on the tragic shooting and that the White House will continue to monitor this terrible situation. Please join me in praying for everyone involved!"

The Hennepin County Sheriff’s Office, assisting in the response, urged residents to avoid the area.

“This is an evolving situation and we will continue to provide updates as more information becomes available," law enforcment officials stated. "Our hearts go out to all those impacted by this act of violence."

The Richfield Police Department noted: "A man dressed in all black and armed with a rifle was reported at the scene."

This is a developing story.