A shooter opened fire Wednesday morning during Mass at a Minneapolis Catholic school, killing two children and injuring 17 other people before dying by suicide, officials said.

The shooting happened at Annunciation Catholic School, just days after the first day of school there on Monday.

Of the 17 injured, police said 14 were children, with their ages ranging from 6 to 15. Authorities said they are all expected to survive.

The shooting comes as school years are starting across the United States, and some universities have dealt with false alarms about school shootings. At least a dozen college campuses faced hoax active shooter calls -- some featuring gunshots sounding in the background.

Here are some of the things to know about the shooting at Annunciation Catholic School.

What Do We Know About the Victims?
The two children who were killed were 8 and 10 years old, officials said. Authorities have not released the identities of the victims, but they said the children who were killed were fatally shot while they were sitting in the church pews.

The three adults who were injured are parishioners in their 80s, officials said. All of the victims have varying injuries but are expected to survive, authorities said.

It is unclear how many people were inside the church at the time. Officials said the shooting occurred near the beginning of Mass, when some children were seated and others were still entering.

What Do We Know About the Shooter?
Minneapolis Police Chief Brian O’Hara said the shooter -- armed with a rifle, shotgun and pistol -- approached the side of the church and shot through the windows toward the children inside before dying by suicide.

He said the shooter, 23-year-old Robin Westman, did not have an extensive known criminal history, acted alone, and had legally purchased the weapons recently.

O’Hara said authorities are aware of video material that the alleged shooter had timed to be released on YouTube. The content has been removed and is under review as investigators try to determine a motive, the police chief said.

In one video that lasts about 10 minutes, the alleged shooter shows weapons and ammunition, many with sayings written on them including the phrases “kill Donald Trump” and “Where is your God?” Some are in Cyrillic.

The person holds up a letter to relatives, sings the word “tomorrow” and says, “I’m sorry to my family ... that’s the only people I’m sorry to.”

A second, almost 20-minute video shows two journals with stickers, some depicting weapons. The alleged shooter flips to what looks to be a drawing of the layout of the church, points to two outside windows and then stabs the illustration with a long knife.

Federal officials referred to Westman as transgender, and the mayor decried hatred being directed at “our transgender community.” Westman’s gender identity wasn’t clear. In 2020, a judge approved a petition, signed by Westman’s mother, asking for a name change from Robert to Robin, saying the petitioner “identifies as a female and wants her name to reflect that identification.”

Former Kentucky state lawmaker Bob Heleringer told The Associated Press he is Westman's uncle, but had not seen Westman in a few years.

“He was my nephew, and I wish he had shot me instead of innocent schoolchildren,” Heleringer said during a phone interview. “I barely knew him. They (Robin’s family) never lived in Louisville. They lived in Minnesota.”

What Do We Know About the School?
The school, which goes from pre-K to eighth grade, had 391 students enrolled for the 2023-2024 school year, according to the National Center for Education Statistics. Each grade level has two classes, with about 20 students in each class.

It is in the city’s Windom neighborhood, about 5 miles (8 kilometers) south of downtown Minneapolis.

The school’s website says teachers “focus on Christian values and civic-mindedness.” Principal Matt DeBoer said that, during the shooting, adults protected the children, with older children protecting younger ones.

President Trump's Comments
President Donald Trump said in a Truth Social post that he was briefed on the “tragic shooting” and that the White House would continue to monitor the situation.

“The FBI quickly responded and they are on the scene,” Trump said in a statement on social media.

“The White House will continue to monitor this terrible situation. Please join me in praying for everyone involved!”

A Nearby Shooting
A shooter killed one person and injured six others at nearby Cristo Rey Jesuit High School on Tuesday afternoon, in what authorities believe was a targeted shooting.

Annunciation Catholic School is about 4 miles (6 kilometers) south of Cristo Rey, and officials do not believe the shootings are linked.

The police chief said Tuesday that a group of adults hanging out near the school were shot, and at least one of them was targeted. There was no mention of anyone from the school being involved in the shooting.