AMNA NAWAZ: Welcome to the "News Hour."

Another mass shooting, this time during mass at a Catholic school in Minneapolis, has left at least two young children dead and another 17 people injured, most of them children.

GEOFF BENNETT: Authorities say they don't yet know of a motive, but said the shooter released a manifesto in social media that has since been taken down.

William Brangham begins our coverage.

WILLIAM BRANGHAM: In South Minneapolis this morning, excitement for the first week of school turned to terror, as an attacker armed with a rifle, shotgun and pistol, opened fire into the windows of the church at Annunciation Catholic School.

As the morning went on, ambulances lined the street, and parents and loved ones, clearly overwhelmed with fear, rushed to the family reunification zone near the school.

EMILY FESTE, Aunt of Shooting Survivors: My husband's a firefighter, and he got a phone call this morning and said that there was an incident at Annunciation.

And that's where my niece and nephew go to school.

We live nearby, so he just took off on foot.

And my brother-in-law is a firefighter too.

But it's so awful and it's so scary.

And I just am really proud of my husband and my brother-in-law for just running into the danger.

And I just pray for the community.

WILLIAM BRANGHAM: The grandfather of a 10-year-old student at Annunciation told the "News Hour" that his grandson was in shock, having seen a friend covered in blood.

BRIAN O'HARA, Minneapolis, Minnesota, Police Chief: The sheer cruelty and cowardice of firing into a church full of children is absolutely incomprehensible.

WILLIAM BRANGHAM: Minneapolis Police Chief Brian O'Hara called this a deliberate act of violence against innocent children.

BRIAN O'HARA: At this point, we know we have a total of 19 victims from this tragedy.

Two were young children, ages 8 and 10, that were sitting in the pews at mass when they were shot and killed.

They were pronounced deceased on the scene.

There were another 14 children between the ages of 6 and 15 that were injured by gunfire.

There were also three adults in their 80s that were parishioners here attending mass that were also shot in this incident.

WILLIAM BRANGHAM: On TRUTH Social, President Trump wrote that he was -- quote -- "fully briefed on the tragic shooting in Minneapolis, Minnesota.

The FBI quickly responded and they are on the scene."

FBI Director Kash Patel said the attacker, who was identified as Robin Westman, is being investigated as having committed an act of terrorism and a hate crime targeting Catholics.

Officials also confirmed the suspect is dead from a self-inflicted gunshot.

Minneapolis Mayor Jacob Frey expressed his anger, noting the children were in the middle of their first mass of the school year.

JACOB FREY (D), Mayor of Minneapolis, Minnesota: And 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.

These are kids that should be learning with their friends.

They should be playing on the playground.

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

And their parents should have the same kind of assurance.

WILLIAM BRANGHAM: Minnesota Governor Democrat Tim Walz said today's tragedy is an all too common occurrence.

GOV.

TIM WALZ (D-MN): We will stand with this community.

We will redouble ourselves to do the best we can to understand what we can do to prevent any parent from having to receive the calls they received today.

WILLIAM BRANGHAM: The principle of Annunciation Catholic urged leaders to do more.

MATTHEW DEBOER, Principal, Annunciation Catholic School: Please pray, But don't stop with your words.

Let's make a difference and support this community, these children, these families, these teachers.

Never again can we let this happen.

WILLIAM BRANGHAM: Over the past two days, mass shootings in Minneapolis have left at least 26 people dead or injured.

Lisa Elm lives blocks away from today's shooting.

LISA ELM, Minneapolis Resident: To hear the sirens is just -- you just don't hear that every day.

And I just wanted to be here to support anyone that needed it.

WILLIAM BRANGHAM: For the "PBS News Hour," I'm William Brangham.

GEOFF BENNETT: Police said the assailant had purchased multiple weapons recently and legally and is believed to have acted alone.

FBI Director Kash Patel also said the shooter identified as transgender.

For more, we're joined now by Minneapolis Democratic mayor Jacob Frey.

Mr. Mayor, we are grateful for you joining us under such painful circumstances.

That two children just 8 and 10 years old were sitting in church pews when they were shot and killed, it is a horror that defies comprehension.

How are you and your community beginning to grapple with this incredible loss and trauma?

JACOB FREY: It's an unspeakable tragedy, but how many times have you heard politicians say that something is an unspeakable tragedy?

What I know about our Minneapolis family here is that they are wrapping their arms around the families of these victims.

These are kids.

Think about them not just as somebody else's kids.

Think about them as your own.

We all have these daily rituals as you send your kids off to school or day care, whether that's putting a headband on or giving them a kiss or whispering a few kind words in their ear.

Every single family should be able to send their kids off to school or church or day care with the assurance that they're going to be safe and they're going to be able to come back.

What I know about Minneapolis is that we are incredibly strong and resilient, and from the teachers that protected these children, literally hiding them under pews, to the faculty at Annunciation, to the law enforcement professionals and police officers that were running towards danger, when so many of the rest of us would have run in the other direction, to the rest of our Minneapolis community that is going to do everything possible that we are wrapping our arms around these families right now.

We're strong.

We're resilient.

We're going to get this -- through this together.

But, yes, obviously, this is horrific.

And it's got to be a whole lot more than words and prayers.

These children were literally praying.

We need action now.

It can't just be, let's say that this will never happen again, we're going to do everything possible to make sure this never happens again.

We got to actually do it.

Now's the time.

GEOFF BENNETT: The 17 people who were injured, 14 of them children between the ages of 6 and 15, to the best of your knowledge, how are they doing?

JACOB FREY: We have had a multijurisdictional approach to make sure that victims of this horrific act of cowardice got to the hospital as soon as possible.

Tragically, there are two kids that are dead.

This could have been a whole lot worse.

And so obviously I'm grateful to everyone that stepped up to keep people safe.

Families have been reunited.

Health professionals and doctors and nurses have been working tirelessly to make sure that people are OK and they get the kind of care that they need.

Mental health response and service is also available to anybody that needs it.

And, at the same time, of course, the community's reeling.

And at the same time, a broader Minneapolis family is committed to doing everything possible to helping these families that are experiencing just an amount of unspeakable sadness and I'm sure anger.

GEOFF BENNETT: Yes.

I want to ask you about the investigation because the FBI is investigating the shooting as an act of domestic terrorism and a hate crime targeting Catholics.

What does that mean in practical terms, both for the investigation and for how the same city understands the motive behind the attack?

JACOB FREY: So I can't speak to everything that the feds are working right now in terms of their investigation, but the Minneapolis Police Department is investigating.

We're working with the state Bureau of Criminal Apprehension.

And we're obviously going to take this investigation wherever it leads.

Obviously, this was an act of hate.

If you don't have some form of hate in your heart, you're not going and shooting up a church with kids.

These were kids.

And so the investigation is ongoing right now.

We're working with a number of different agencies and organizations to make sure that we get to the bottom of every last question, and we will follow it wherever it leads.

GEOFF BENNETT: Minnesota has a red flag law that allows firearms to be temporarily removed from people who are deemed to be a danger to themselves or to others.

We don't know enough about what transpired to know whether that would have prevented this tragedy.

But how does it work?

And what more needs to be done at the state and federal level to prevent another tragedy like this from happening again?

JACOB FREY: I can't speak to all the specific circumstances of this tragedy.

And so I also can't speak of what would have prevented it from happening.

But, generally, generally speaking, let's just be very real here.

We have too many guns in America.

When you have more guns than you have people, you have got a problem.

When people are able to get guns that are in some form of severe mental health crisis, you got a problem.

If you have school shooting after school shooting and church shooting after church shooting, and it continues to happen, you got a problem that would say to most reasonable people, you got to do something about it.

This, by the way, has happened in other countries like once or twice and then they do something about it.

We owe this to our children.

This should be not out of hate for any community.

This should not be out of hate for any sort of politician.

This should be out of love for our kids.

I am a father of a 4.5-year-old.

I'm the father of a 3-week-year-old.

And we have all got titles in our professional lives, but the titles that matter most to me are husband and dad.

I'm not unique.

We need to understand how much we love our kids and make sure that we're imparting that love on every single member of our community.

It's on us now to act.

GEOFF BENNETT: Mayor Jacob Frey, you and your city are very much in our thoughts as you navigate this tragedy.

Thank you for your time this evening.

JACOB FREY: Thank you so much for having me.