Chief of Police John Drake named the suspect as Audrey Hale — a 28-year-old female, who the officer later said identified as transgender.

Hale had maps of the school, left behind a manifesto, and was “prepared for a confrontation with law enforcement,” the police chief told reporters following the latest outburst of gun violence to stun the United States.

Armed with at least two assault rifles and a handgun, Hale entered the Christian Covenant School from a side entrance, allegedly shooting through a door — firing multiple shots while advancing through the building, according to police.

They said officers were on the scene within about 15 minutes of receiving the first emergency call around 10:00 am (1500 GMT), engaging the shooter who returned fire before being shot dead.

Police identified the six victims, saying one of the three children was eight years old and two were age nine, while the adults killed were age 60 to 61.

Television images showed young children holding hands as they filed out of the school, and one searing photograph showed a child sobbing through the window of her yellow school bus as it pulled away from the crime scene.

Avery Myrick said her mother, a pre-kindergarten teacher at Covenant, hid as shots rang out through the school.

“She said she was hiding in the closet, and that there was shooting all over and that they had potentially tried to get into her room, and just that she loved us,” Myrick told WSMV4 television, an NBC local affiliate.

When she heard her mother was safe it brought “a ton of relief.”

“But you know, you’re still hurting for the people out there who might not get that call,” she said.

School shootings are alarmingly common in the United States, where the proliferation of firearms has soared in recent years.

President Joe Biden described the latest shooting as “sick” and said gun violence was tearing the nation’s “soul,” as he urged Congress to pass a ban on the assault weapons commonly used in mass shootings.

“It’s ripping our communities apart, ripping the soul of this nation, ripping at the very soul of the nation,” he said.

A Nashville fire department spokesperson, Kendra Loney, said all unharmed students were escorted out of the building with faculty and staff.

“But we are sure that they heard the chaos that was surrounding this, so we do have mental health specialists and professionals that are at that reunification site for both the students and the families.”

The Covenant School is a private Presbyterian institution with just over 200 students in preschool to roughly age 12.

Local newspaper The Tennessean quoted a police spokesperson as saying the suspect Hale, a former student at the school, was now an illustrator and graphic designer who used he/him pronouns. Police had initially identified him by his birth gender.

Drake said investigators were working on a possible motive but said it was “not confirmed.”

Asked whether Hale’s gender identity may have been a factor, Drake said: “There is some theory to that, we’re investigating all the leads.”

There have been 129 mass shootings — defined as incidents in which four or more people were shot or killed — so far this year, according to data from the Gun Violence Archive.

Biden’s calls for Congress to reinstate the national ban on assault rifles, which existed from 1994 to 2004, has run up against opposition from Republicans, who are staunch defenders of the constitutional right to bear arms and have had a narrow majority in the House of Representatives since January.

Just hours after the shooting, pro-firearm organization Gun Owners of America assailed Biden as “the man responsible for making schools soft targets,” and repeated their call to allow teachers to arm themselves in classrooms.

“When will we start to have conversations about real solutions for hardening schools & protecting kids? Armed teachers are a 100 percent effective deterrent!” the group tweeted.

The deadlock in Washington has come despite public uproar over high-profile massacres such as the one at Sandy Hook elementary school in Connecticut in 2012, when 26 people, including 20 children, were killed.

Last year a shooter in Uvalde, Texas, killed 19 students and two teachers.

Between those two tragedies, the murder of 14 students and three staff members in Parkland, Florida in 2018 fueled a nationwide movement, led by young people, to demand stricter gun controls — but failed to spur significant action in Congress.