Two people have been taken to hospital and three people arrested after what police said was a "distressing incident" in Aberdeen city centre.
It comes after a disturbance involving a number of people in the Union Terrace area at about 20:00 on Saturday.
Police said a 44-year-old man and a 17-year-old girl were taken to the city's royal infirmary, where the man remains in a serious condition.
A 20-year-old woman has been arrested along with two boys aged 15 and 17.
They are all expected to appear Aberdeen Sheriff Court on Tuesday.
Extra police patrols
Det Insp David Howieson said officers had spoken to a number of people in connection with the incident.
He added: "We know that a number of people were in the area at the time and I would specifically ask anyone who may have filmed or photographed the incident to come forward.
"This was a distressing incident for those involved, however incidents of this type are rare in Aberdeen and extra police patrols will be on duty in the city centre over the course of the holiday weekend ensuring people can safely enjoy the area."