A man has been arrested on suspicion of murder after three people were killed in the city.
Police were called to Ilkeston Road just after 4 am where two people were found dead in the street.
Officers were then called to another incident in Milton Street where a van had attempted to run over three people.
They are currently being treated in hospital.
A man has also been found dead in Magdala Road.
Police have arrested a 31-year-old man on suspicion of murder and he remains in police custody.
Chief Constable Kate Meynell said: “This is an horrific and tragic incident which has claimed the lives of three people.
“We believe these three incidents are all linked and we have a man in custody.
“This investigation is at its early stages and a team of detectives is working to establish exactly what has happened.
“We ask the public to be patient while inquiries continue. At this time, a number of roads in the city will remain closed as this investigation progresses.”
The following roads are currently closed –
Woodborough Road from junction of Magdala Road into the city,
Maid Marian Way junction of Parliament Street.