A 25-year-old man has been raped after approaching a man for a cigarette.
The attack happened in the early hours of Friday near Dowanhill Park in Glasgow's west end.
Strathclyde Police said the man was walking near Hyndland Street and Highburgh Road between midnight and 2am when he approached a man for a cigarette.
The man subjected him to a serious sexual assault before making off from the area.
The suspect is described as white, heavily built, 6ft and in his early 20s.
He had fair hair and wore a long black jacket and satchel-type bag across his body. He is also described as having an east coast accent.
Detective Inspector Steven Watson said: "This young man has suffered a frightening experience and is very distressed by the incident.
"I would ask that anyone who saw someone fitting the description and or acting suspiciously to contact police."
Officers are particularly keen to talk to a man aged 20-25 who the victim spoke to after the attack.
He wore a light-coloured hooded top and had a local accent.