An employee at a Walmart supermarket in the US state of Virginia has shot dead six people and injured six others.
Officers were called to the busy branch in Chesapeake after the gunman opened fire on colleagues in a staff room.
He then turned the gun on himself and died of a self-inflicted gunshot wound, officials said.
There is no clear motive for the shooting. Police are not searching for anyone else in connection with the attack.
The police have identified the gunman as 31-year-old Andre Bing, and they said he was armed with a handgun as well as multiple magazines.
Walmart said he was an “overnight team lead” who had been employed there since 2010. “We are focused on doing everything we can to support our associates and their families,” the company said.
Of the six injured, two are known to be in a critical condition while one is in a stable condition.
The first call to police was made at 22:12 local time on Tuesday (03:12 GMT Wednesday) and officers arrived at the supermarket within two minutes.
They entered the building shortly after, and the scene was declared safe around an hour later once it had been cleared and all the victims had been located.
Processing the crime scene would likely take several days, Police Chief Mark Solesky told a news conference on Wednesday, adding that the investigation was being carried out with the help of the FBI.
An eyewitness – who was wearing a Walmart uniform – described what happened in footage that circulated on social media shortly after the attack.
He said he had left a staff room, which a colleague then entered before quickly opening fire.
One woman told WAVY-TV that her brother, a 20-year-old employee, was shot and wounded just 10 minutes after signing on for work.
But she said her sibling had been able to talk to relatives and send texts, something she said was “comforting”.
Another woman, Joetta Jeffery, told CNN that her mother had been inside the building when the attack took place, and had managed to send text messages.
Ms Jeffrey said her mother was not hurt but was in shock.
Republican Virginia Governor Glenn Youngkin, meanwhile, ordered flags to be flown at half-mast to mark the tragedy.
“There will be time for us to react and better understand but today is a moment where we need to support these families that are facing the unimaginable,” he said.
President Joe Biden described the attack as “another horrific and senseless act of violence”.
“I signed the most significant gun reform in a generation, but that is not nearly enough. We must take greater action,” he said.
The shooting comes just days after a gunman opened fire at a LGBT nightclub in the US state of Colorado, killing five people and injuring 17 others.
And earlier this month, three American Football players were shot and killed at the University of Virginia.