At least eight people were killed in a shooting in the US city of Indianapolis by a gunman who is believed to have then killed himself, police said.
The victims were all found at a Fedex facility near the international airport where the shooting took place late Thursday, police spokeswoman Genae Cook told a news conference, adding several others had been taken to hospital.
One man who said he works at the plant told local broadcaster WISH-TV he saw the gunman start shooting and heard more than 10 gunshots.
"I saw a man with a sub-machine gun of some sort, an automatic rifle, and he was firing in the open. I immediately ducked down and got scared," Jeremiah Miller said.
Mr Cook told reporters officers had responded to an "active shooter incident," adding they believe the gunman died by suicide.
She said authorities judged there was no longer an immediate threat to public safety.
A Fedex spokesperson confirmed to AFP that its facility was the scene of the shooting, and said the company was cooperating with authorities.
"We are aware of the tragic shooting at our ground facility near the Indianapolis airport," the company said in a statement.
"Safety is our top priority, and our thoughts are with all those who are affected."
The facility for the delivery company is reported to employ more than 4,000 people.
Timothy Boillat, another employee at the facility, told WISH-TV that he saw around 30 police cars arriving at the scene as he witnessed the shooting unfold.
"After hearing the shootings, I did see a body on the floor," he said.
"Luckily, I was far enough away to where he [the shooter] didn't see me."
Spate of fatal shootings:
Live video showed police tape at the scene of the incident, which follows several mass shootings in recent weeks.
At the end of last month, four people, including a child, were shot dead in an office building in southern California.
On March 22, 10 people were killed in a shooting at a grocery store in Boulder, Colorado.
That came less than a week after a man shot and killed eight people, including six women of Asian descent, at spas in Atlanta, Georgia.
Nearly 40,000 people in the United States die each year from guns, more than half of those being suicides.
The issue of gun regulation in the United States is politically fraught.
President Joe Biden this month announced six executive measures he said would help stem the gun violence crisis.
"It's an international embarrassment," Biden told Congress members and gun control activists at a White House ceremony.
"Enough prayers," the Democrat said. "Time for some action."
The move was immediately attacked by Republicans, with the party's senior leader in the House of Representatives, Kevin McCarthy, warning of "unconstitutional overreach."
Chauvin trial nears end
The shooting comes as the trial against former police officer Dereck Chauvin, who is accused of killing black man George Floyd, comes to an end.
Closing arguments are set to begin Monday, after which a racially diverse jury will begin deliberating at a barbed-wire-ringed courthouse in a city on edge - not just because of the Chauvin case but because of the deadly police shooting of a 20-year-old Black man in a Minneapolis suburb last weekend.
Before the jury was brought in Thursday, Chauvin, his Covid-19 mask removed in a rare courtroom moment, ended weeks of speculation by informing the judge he would invoke his Fifth Amendment right not to testify.
Shortly afterward, the defense rested its case, after a total of two days of testimony, compared with two weeks for the prosecution.
Judge Peter Cahill reminded the jurors they will be sequestered starting Monday and said: "If I were you, I would plan for long and hope for short."
Chauvin, 45, is charged with murder and manslaughter in Mr Floyd's death after the 46-year-old Black man was arrested on suspicion of passing a counterfeit $20 at a neighborhood market last May.