A bare-chested man was reported to be brandishing a knife in a crowd which had gathered in the Templemore Avenue area of east Belfast in the early hours of the morning.
An 18-year-old man sustained stab wounds to his neck, chest and arm during the incident.
This was one of two assaults which occurred at around 4am and which police are investigating.
They received a report shortly that a large crowd, of between 30 and 40 people, was gathered at Templemore Avenue.
Officers attended the scene and the crowd was moved on.
A short time later, however, it was reported a number of people had again assembled on the street and police say a man was in the area brandishing a knife.
He is described as being around 6ft tall, and was bare chested and wore grey tracksuit bottoms.
Police say an 18-year-old man sustained stab wounds to his neck, chest and arm and was taken to hospital for treatment for his injuries which are not believed to life threatening at this time.
A second man, also aged 18, was reported to have sustained cuts to his arm and shoulder and scratches to his ear after he was assaulted by three men in the area.
Sergeant Austin Grant is appealing to anyone who was in the area and saw what happened or anyone who has information which may assist the investigation to get in touch by calling the non emergency number 101, quoting reference number 327 of 10/03/19.
Alternatively information can also be provided by calling the independent charity Crimestoppers on 0800 555 111.