A man was taken to hospital with "significant facial injuries" after being subjected to a vicious attack in Glasgow city centre.
Police said the incident happened as two 38-year-old men were walking north on Sauchiehall Street, near Cambridge Street, at 00:15 on Thursday.
They were attacked by three men and two women.
Both men were taken to hospital but the second man was released after treatment for minor injuries.
The condition of the man with facial injuries has been described by staff as stable.
Police said the suspects were all about 18 years old.
'Attack was vicious'
The first man was black, slim and wearing dark clothing. The second man was white, slim, and wearing a checked shirt, dark jacket and dark jeans and the third man was white, slim, and wearing a black puffa jacket and black baseball cap back to front.
The first woman was described as being black, slim, and wearing a black leather jacket and dark trousers.
The other woman was mixed race, slim and wearing a black jacket, grey T-shirt, dark jeans and was carrying a white shoulder bag.
Det Insp David MacGregor, of Greater Glasgow CID, said: "The two men had been out for the night and were walking on Sauchiehall Street in the direction of Charing Cross.
"They spoke with the group of men and women as they passed them but the group turned on both men and assaulted them.
"The attack was vicious, leaving one of the men with a serious facial injury which may lead to scarring."
He added: "Officers are currently checking CCTV in the area, however, there were a number of people in the street at the time who I am sure saw what happened.
"I would appeal to them, or indeed anyone with information, to contact us."