Armed police have been shot at after being called to an incident off King's Road in Chelsea, west London.
It followed reports of gunshots in Markham Square around 4.50pm.
They came under fire at the scene and a police spokesman confirmed that officers fired back.
One eyewitness told Sky News: "From what I heard it seems to have been a domestic argument.
"I was in one of the stores three or four doors down from where it happened.
"I was in a changing room and a lady came in very panicked and crying and screaming a little bit.
"It seemed that her ex-partner was the one shooting - I don't know if he was shooting at her.
"It seemed that an argument started and, as she put it, it got out of hand. There was also a gentleman with her. I don't know if he was anything to do with the argument but it seems that it was of that nature."
Eyewitness Bill told Sky News: "I heard six or seven shots coming from an area near a bank - they sounded like fire-crackers. Police arrived and started to push people back."
There have been no reported injuries and the area has been sealed off.
A police officer at a cordon told local residents that shots were fired out of a jewellery shop called Folli Follie on the King's Road opposite the entrance to Markham Square, although this could not be confirmed.
Shop manager Shan Nimalakumar, 36, was locked in health store Holland and Barratt with one customer and two members of staff.
He said: "The police won't let us anywhere near. We are now stuck in the shop. They said 'stay in the shop, lock the door and go to the back'."
A number of shops on the stretch of King's Road facing Markham Square have been forced to close.
A waiter in the Benihana restaurant said he and around 15 members of staff were stranded in the building. He added: "I heard gun shots when I was outside, it was scary."
A woman who lives near the scene of the shooting was seen at the cordon telling police she had reported hearing the gunfire.
She refused to give her name, saying only: "I would rather not talk, it's really spooky."

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