A man was stabbed by a group of men armed with baseball bats and knives as “distressed” children looked on, witnesses have said.
The 24-year-old victim was attacked in Nursery Row Park, Walworth, south London, at about 17:20 BST on Friday.
The victim reportedly collapsed in the middle of East Street Market as traders were packing away for the evening.
He remains in a critical condition, the Metropolitan Police said. No arrests have been made.
Two sisters, who saw the victim lying in the street following the attack, said children witnessed what happened.
One said she saw two children, who looked about five or six, explain to police how a gang of men had run up to the victim and stabbed him.
“They (the children) were really distressed,” she said.
She said her sister, a former nurse, went to help but was stopped by officers.
“There was a lady trying to put the young man in the recovery position but they weren’t letting anyone else come near him,” she said.
‘Get attacked again’
Her sister said: “They will come back for that person – we used to see it all the time when I was a nurse,” she said.
“(Stab victims) need security when they get out of hospital because they always get attacked again.”
Det Sgt Rob Merrett said forensic analysis of the scene and a trawl of available CCTV footage was under way.
He urged witnesses and anyone with mobile phone footage of the attack to come forward.
A Section 60 order, which allows police officers to stop and search people, was authorised for the Walworth area and additional patrols have been put in place.