A woman has been shot by police in a street.
Officers were called to reports of a woman armed with a knife in Cairns Street, Toxteth in Liverpool, at about 13:50 BST.
She suffered an injury to her upper body and has been taken to hospital for treatment. Her condition is unknown.
Merseyside Police said it was an “isolated incident” and the shooting had been referred to the Independent Office for Police Conduct (IOPC).
North Hill Street remains cordoned off and there will be an increased police presence in the community in the next few days, the force said.
Supt Diane Pownall said: “I know that people in the Toxteth area and the wider communities of Merseyside may feel shocked by the incident that has taken place today.
“This was an isolated incident in which officers responded to a number of members of the public reporting a woman in possession of a knife in the Toxteth area.”
Police are not looking for anyone else.
A woman who lives near the police cordon said she had been asleep after working a night shift when she was woken by a gunshot.
“I heard a bang. I didn’t know what had happened until my daughter told me she had seen it on the news,” she said.
A neighbour, who did not want to be named, heard two loud bangs.
She said: “It sounded like something had blown up.”
Another resident said: “People are sad and mad about it but obviously we don’t know who she is or what’s happened yet.
“A lot of people are going to be angry that a police officer has felt the need to shoot a bullet into somebody.”
An IOPC spokesman confirmed an investigation had begun.
He said: “The incident was referred to us, as is mandatory in these circumstances, at 2:45 pm.
“Our investigation is in its very early stages and we have investigators attending the scene and the post-incident procedures to begin gathering evidence. The woman is currently being treated in the hospital.
“Our thoughts are with everyone affected by this incident.”