Five men were treated in hospital after two attacks in Brighton which police believe were carried out by the same people.
Sussex Police said: “Police are investigating two incidents which occurred in Brighton just after midnight on Sunday 12 August.
“A man was assaulted in Castle Square.
“The 23-year-old was talking on the phone when he was approached by three men and was threatened with a knife after demanding his phone.
“He was then kicked and punched by the three men.
“The victim was treated at the Royal Sussex County Hospital for cuts and bruises to his face.
“This assault is being linked to a similar one a few minutes earlier in Prince’s Street, just off Edward Street, where four men were assaulted and injured by five men.
“The victims were taken to hospital with minor injuries.”
Detective Constable Chris Clarke said: “We believe these two assaults might be linked and we are appealing to anyone who was in the Old Steine area around midnight on Sunday who might have seen something to get in touch.
“One of the suspects was described as black, between 18 and 20 years old, 5ft 10in, with a crewcut style haircut, skinny build, London accent, wearing navy Adidas tracksuit with white stripe, black rucksack and police style baton.
“Another male was described as white, 5ft 9in, average build, about 19, crewcut style hair, grey hoodie, tracksuit bottoms and a London accent.
“Anyone with information or witnesses are asked to contact police online quoting serials 39 or 6 of 12/08.”