At least three children and three staff members were killed after a mass shooter opened fire at a primary school in Tennessee on Monday, officials said.
Police killed the assailant, 28, after they responded to the shooting at The Covenant School on Monday morning, Nashville Metro Police said.
The shooting occurred in a “lobby-type area” in the upper level part of the private school and not in a classroom, Nashville police spokesman Don Aaron told reporters.
The shooter was armed with two “assault type rifles” and at least one pistol. Two police officers who were part of a five-member team killed the shooter at 10.27am local time.
Officers began clearing the first storey of the school when they heard gunshots coming from the second level, Mr Aaron said.
Police later said the shooter fired at arriving officers from a second-storey window and was armed with significant ammunition.
Nashville Police identified three nine-year-old pupils fatally shot as Evelyn Dieckhaus, Hallie Scruggs and William Kinney.
They said Cynthia Peak, Katherine Koonce and Mike Hill were the adults killed in the shooting.
The website of The Covenant School lists Koonce as head of the school.
One officer suffered an injury from broken glass.
“There is video from the school that we are viewing now to try to learn exactly how all of this happened,” Mr Aaron said.
Police said the shooter was Audrey Hale, a resident of Nashville.
There was no immediate official word on a possible motive for the gun violence but the suspect had drawn detailed maps of the school, including entry points for the building.
Hale also left behind a “manifesto” and other writing that investigators were examining, Police Chief John Drake told a briefing.
He said in an interview with NBC News that investigators believe the shooter had “some resentment for having to go to that school.”
President Joe Biden was briefed on the shooting, White House press secretary Karine Jean-Pierre said.
Mr Biden later spoke of the shooting before a White House event.
“It's heartbreaking, a family's worst nightmare,” he said.
“We have to do more to stop gun violence. It's ripping our communities apart, ripping the soul of this nation, ripping at the very soul of the nation.
“And we have to do more to protect our schools so they aren't turned into prisons.”
Three children were pronounced dead after arriving at Monroe Carell Jr Children's Hospital at Vanderbilt University Medical Centre, outlets reported, quoting hospital spokesman John Howser.
Police have set up a reunification area for parents and pupils at a nearby church.
Mr Biden's wife, Jill Biden, said she was “truly without words” as reports of the Tennessee shooting came in.
“Our children deserve better,” she told the National League of Cities conference in Washington.
“We stand, all of us, we stand with Nashville in prayer.”
Tennessee Governor Bill Lee said he was closely monitoring the situation and state forces were assisting local officials and emergency workers.
“As we continue to respond, please join us in praying for the school, congregation and Nashville community,” Mr Lee said in a tweet.
The Covenant School is a Christian establishment founded in 2001 as part of Covenant Presbyterian Church.
In the Green Hill neighbourhood just south of downtown Nashville, the grade school has 33 teachers and about 260 pupils, the school's website said.
The Covenant School teaches children pre-kindergarten to Grade 6.
The school held active shooter training programme last year, WTVF-TV reported.
Mass shootings are a common occurrence in the US, with more than 129 reported this year, data from the Gun Violence Archive showed.
The GVA defines a mass shooting as incidents where four or more people were shot or killed in a single event, not including the shooter.
Deadly shootings last year — including the deaths of 21 children at a school in Uvalde, Texas — launched renewed bipartisan efforts to pass gun-control legislation designed to expand background checks.
Mr Biden has pushed for even stricter measures, including a nationwide assault weapons ban.
“We have to do more,” Ms Jean-Pierre said, adding that Mr Biden will continue to call on Congress to act on gun control.
