Victims were left with broken jaws when 'violent' thugs punched them in the face during a string of robberies in the Northern Quarter.
The attacks happened in the early hours of yesterday (Sunday).
Police said three men carried out seven separate robberies between 2am and 4am.
The victims were punched 'with no warning' as a means to shock them before they had items stolen from them.
A total of five people, aged between 20 and 60, were rushed to hospital following the attacks.
It is unclear how many of the five suffered broken jaws, city centre Councillor Pat Karney said.
Some of the victims remain in hospital.
The robberies were carried out on Oldham Street, Tib Street, Piccadilly Gardens, High Street and Newton Street.
Police described the attackers as three men, aged between 20 and 40.No arrests have been made and police are examining CCTV footage from the area.
Det Sgt Kat McKeown of GMP’s City of Manchester Division said:
This was a series of violent robberies during which victims have been set upon by three men intent on causing them harm.