There are fears of reprisal attacks after nine people were stabbed at a party in Melbourne's CBD.
A 19-year-old man was among those stabbed when a gathering at a short-term rental apartment on Spencer Street turned violent.
The Dandenong North man flagged down police at Southern Cross Station about 2.20am on Monday, telling officers he'd been stabbed after a fight broke out.
He was hospitalised in a critical condition with several upper body wounds.
Three 17-year-old boys, four 19-year-old men and a 20-year-old man were also stabbed at the party.
They took themselves to various hospitals. None of their injuries were life-threatening.
Commander Darren Franks acknowledged parties at short-term rentals were sometimes connected to gangs and said police feared more violence could play out.
"We understand that emotions and tempers run high after events like this so one of our biggest concerns is reprisal behaviour," he told reporters.
"It is extremely worrying for us."
He said the victims are reluctant to co-operate with police.
"We're struggling to find out the why and the how in regards to how it was started," he said.
Police are yet to establish who booked the apartment and what platform was used.
Australian Associated Press