Five people were killed and several others injured when a gunman opened fire at an industrial park in the US state of Illinois, police there say.
The gunman was also killed, a police spokeswoman said. She added that the five officers had been hit by gunfire.
The attack on Friday took place in Aurora, a suburb about 40 miles (65km) west of Chicago.
It comes a day after the first anniversary of a school shooting in Parkland, Florida, which left 17 dead.
Friday’s shooting is reported to have taken place at Henry Pratt Company, a manufacturing firm that makes valves for large water pipes.
Police named the gunman as Gary Martin, 45, who they said had been an employee at the company.
What have police said about the shooting?
Police received reports of an “active shooter” in Aurora at about 13:24 local time (19:24 GMT), Aurora police chief Kristen Ziman said at a press conference.
They were “fired upon immediately” when they arrived at the scene, she said.
Ms Ziman added that a rescue task force was quickly deployed to the industrial park, accompanied by the emergency services, including the fire department and paramedics.
Chris Southwood of the Illinois Fraternal Order of Police described the Aurora officers who attended and were shot as “courageous”.
“[These] officers and their colleagues did not hesitate to literally put their lives on the line today to stop further bloodshed,” Mr Southwood said in a statement.
Of the five officers wounded, two were airlifted to nearby trauma centres.
The identities of the victims have not yet been released.
How have witnesses described the scene?
Witness John Probst, who works at the Henry Pratt Company, earlier told broadcaster ABC7 that he saw the attacker, whom he recognised as a colleague.
He said the man was carrying a handgun equipped with a laser sight, but this has yet to be confirmed by officials.
“One of the guys was up in the office [and] he said this person was shooting, and, he come running down and he was bleeding pretty bad, and the next thing you know he was walking back and forth, I heard more shots, and we just left the building,” Mr Probst said.
An employee at nearby Capitol Printing told ABC7 that they had hid in a closet when the shooting began.
Others in nearby buildings said they locked themselves in.
Police in Aurora, Colorado – where a man opened fire in a crowded movie theatre in 2012 – quickly tweeted that the incident was not happening in Colorado.
Illinois Senator Tammy Duckworth said: “This is a scary, sad day for all Illinoisans and Americans.”
President Donald Trump has been briefed on the incident, according to White House spokeswoman Sarah Sanders.