The fight started after a number of people visited NU Bar from London
Police believe a Stanley knife was used to stab six people during a mass brawl in Northampton town centre.
The fight, which took place at 04:00 GMT on Friday, involved between 50 and 60 people and took in Faces and NU Bar on Bridge Street.
Northamptonshire Police officers have been reviewing CCTV images, but no arrests have been made.
Ch Insp Mark Evans said increased numbers of officers had been working in the run up to Christmas.
A total of eight people were injured during the brawl, with six receiving stab wounds.
Faces and NU Bar have had their licences revoked for seven days pending a full review
Three have been receiving treatment at University Hospital Coventry and five at Northampton Hospital. All are said to be in a stable condition.
Det Insp Ally White from Northampton CID called the investigation "complex" with "multiple victims who had travelled to Northampton for a night out and ended up in hospital".
"A sharp implement, possibly a Stanley knife, is believed to have been used to stab the victims," he said.
He said a number of people had travelled to NU Bar for the night and "when tensions began to rise" and the venue was closed, they had moved on to Faces where the fight broke out.
Six people were taken to hospital after being stabbed
Northampton's operations commander, Ch Insp Evans, said officers would be on patrol in Bridge Street on Thursday night to speak to potential witnesses.
He said police were using "every available power" to make sure there is no re-occurrence of the incident.
"We have been working with an increased number of police officers for a number of weeks," he said.
"I can reassure the public this increase in numbers will also be in place this weekend."
Northampton Borough Council's licensing sub-committee suspended the licences of NU Bar and Faces for seven days on Friday.
- Published13 December 2014
- Published12 December 2014
