A man had his neck slashed with a blade from behind in an "unprovoked" attack in Bournemouth town centre.
Two local men aged 56 and 59 have been arrested on suspicion of attempted murder after a search by armed police.
The 18-year-old victim was taken to hospital with serious but not life-threatening injuries after the assault in Old Christchurch Road, said police.
He was left with "a serious cut to the neck" by a man who fled the scene toward Wootton Gardens early on Friday.
Dorset Police issued CCTV images of a suspect, who was described as white and was wearing grey jogging bottoms, blue trainers with white soles, and a black jacket with a white top underneath.
Det Con Matt Cooke said: "This was a serious and unprovoked assault."