Detective are continuing to question two men arrested on suspicion of attempted murder following stabbings in Sheffield.
The two men were arrested yesterday after multiple stabbings and clashes between groups in the city centre which left five people injured.
Two further men who were arrested for public order offences have been released from custody.
One has been released under investigation while the other faces no further action.
Police said two fights broke out close to Barker's Pool in the early hours of Saturday leaving five people injured - four with stab wounds.
(http://www.thestar.co.uk/news/update-multiple-stabbings-in-sheffield-not-terror-related-1-8781136|Multiple stabbings not terror related}
The first fight was reported to police at about 4am in Cambridge Street and resulted in an Asian man being stabbed.
At around 5.53am there was a second brawl in Carver Street, in which three Polish men were stabbed. All three remain in hospital, where one is in a 'serious but stable' condition.
A fifth man who was hit on the head with a bottle during the second fight was treated for minor injuries and released from hospital.
Members of the public and people who work in bars close by told how the incidents had put them 'on edge'.
Jessica Walton, aged 24, who lives on West Street, said: "I have only just moved here so it puts me a bit on edge. "My family members visited and saw all the police there and were shocked. "I'll be avoiding this area at night."
Her 24-year-old friend, who did not want to be named, added: "It always makes you wonder in this day and age if it's a terror attack, that was my first thought.
"Things like this happen in city centres, but usually it's a one-off. To have five people injured is a lot. It must have been a huge fight."
Helena Trabucchi, aged 20, who works at the Tap and Tankard in Cambridge Street, just yards from one of the incidents, said: "We couldn't get to the pub this morning because of the police cordon. It's a little scary.
"Sadly these things happen in busy city centres sometimes. You can't really criticise police though because they have arrested a few people."
Police said the attacks were not terror related following speculation on social media.
Witnesses are urged to call 101. Alternatively call Crimestoppers anonymously on 0800 555111.