Eight people have been killed and seven injured in a shooting at a FedEx facility in the US city of Indianapolis, police say.
The gunman began shooting “randomly” almost immediately after exiting his car, according to police.
He apparently killed himself minutes before police arrived, officials say. They have not confirmed the identities of the victims or the gunman.
This is the latest incident in a recent uptick of mass shootings across the US.
The attack began around 23:00 local time (03:00 GMT) on Thursday in Indianapolis, Indiana – the state capital and its largest city.
In a news conference on Friday, city officials said no motive had been established yet, and noted that one may never be determined.
“We’ll never really know all the ins and outs of why this occurred, but we’ll try our best,” said police chief Randal Taylor.
Craig McCartt, the deputy chief of criminal investigations, said that the gunman began firing as soon as he arrived at the building.
“This suspect came to the facility and when he came there, he got out of his car and pretty quickly started some random shooting outside the facility,” he said.
“No confrontation or argument, he just appeared to randomly start shooting,” he added.
Four people were found dead outside the building, and another four inside.
The attacker, who appeared to have shot himself “minutes” before police arrived, was also found inside the facility.
“When officers arrived they found a very chaotic and active crime scene,” Mr McCartt said, adding that they believe the gunman used a rifle during the attack.
Mayor Joe Hogsett paid condolences to the victims and called for Americans to tackle the “scourge of gun violence that has killed far too many in our community and in our country”.
He also called for people to fight against “the assumption that this is how it must be and we might as well get used to it”.
“We need the courage that compels courageous acts.”
The FBI, which is assisting in the investigation, has been searching a residence in the area, officials said, but they refused to answer whether it was the suspect’s home.
‘He was firing in the open’
A FedEx statement said the company was aware of the shooting and co-operating with the authorities.
“Safety is our top priority, and our thoughts are with all those who are affected,” it said.
Local media quoted FedEx worker Jeremiah Miller as saying he had seen the gunman firing.
“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,” he said.
This is the third mass shooting in Indianapolis this year. Five were killed, including a pregnant woman, in a shooting in January. In March, three adults and one child were killed after an argument broke out over a coronavirus stimulus cheque.
The Gun Violence Archive puts the number of gun violence deaths from all causes at 12,395 so far this year in the US, of which 147 were in mass shootings. Last year saw a total of 43.549 deaths, and 610 in mass shootings.
Last week, President Joe Biden announced his first steps since taking office to tighten gun controls following a series of mass shootings.
It includes efforts to set rules for certain guns, bolster background checks and support local violence prevention.
In a statement after this latest shooting, Mr Biden said: “We can, and must, do more to act and to save lives.”
“God bless the eight fellow Americans we lost in Indianapolis and their loved ones, and we pray for the wounded for their recovery.”