Emergency services were called to East Shore Way in Milton just after 8am today.
Police and paramedics were called to the scene.
A cordon still remains in place this afternoon.
A 30-year-old woman, a 27-year-old woman, both from Portsmouth, and a 30-year old woman from Brighton, have been arrested on suspicion of grievous bodily harm.
Police have also said a 30-year-old woman from Portsmouth has been arrested on suspicion of affray.
Here are our latest photos from the scene.
1. East Shore Way
Pictures of police in East Shore Way, Milton, this afternoon. Picture: Stuart Vaizey Photo: Stuart Vaizey
2. East Shore Way
Pictures of police in East Shore Way, Milton, this afternoon. Picture: Stuart Vaizey Photo: Stuart Vaizey
3. East Shore Way
Pictures of police in East Shore Way, Milton, this afternoon. Picture: Stuart Vaizey Photo: Stuart Vaizey
4. East Shore Way
Pictures of police in East Shore Way, Milton, this afternoon. Picture: Stuart Vaizey Photo: Stuart Vaizey