Dramatic pictures show medics treating a person following a stabbing in central London.
Police say the incident - which took place on Bishopsgate at around 9:45am on Thursday (6/10) - is being treated as a suspected robbery.
Three people were stabbed and a person was pushed to the floor, according to City of London Police.
Reports suggest that the incident unfolded over a phone theft gone wrong, though this has not been confirmed.
It is unclear if any arrests have been made.
Photos show multiple ambulances and police cars parked up, with a screen around a person on a gurney.
An onlooker said: "I was working across the road from where it happened, and when I went to get a coffee, I saw the commotion.
"There were ambulances and police everywhere - it looked like a real bloodbath.
"They're saying the stabbing happened after bystanders challenged a bike thief - I'm just hoping the victims pull through."
City of London Police said: "We received reports of three stabbings & a person pushed to the floor on Bishopsgate at 9.46am & officers arrived at the scene at 9.51am.
"Three victims were taken by LAS to a nearby hospital to be treated. This is an ongoing situation, but is not being treated as terror-related.
"This incident is being treated as a suspected robbery. Investigations are ongoing."
Footage allegedly taken on a nearby street shows a man being arrested, although it is unconfirmed if this is related to the stabbing.