The victim of the brutal assault is currently in a critical condition in hospital.
One man has been arrested detectives over the vicious attack.
Detective Inspector Adrian Burns said: “The assault was reported to have occurred at the lower end of Carlisle Road close to the roundabout at around 4.50 pm on Sunday afternoon.
“It was reported that a man, aged in his 30’s, was punched and kicked by a number of males leaving him with serious head injuries.
“The injured man was taken to the Royal Victoria Hospital in Belfast following the incident and he remains in the Intensive Care Unit today in a critical condition.
“A 27 year old man has been arrested on suspicion of grievous bodily harm and he remains in custody at this time assisting with our enquiries.
“This was a brutal attack on a defenceless man.
“I would appeal to anyone who was in the area on Sunday afternoon and witnessed the assault, or saw a group of males in the area of the steps between Carlisle Road and John Street, to contact detectives in Strand Road on 101 quoting reference number 1296 3/5/20.
“Alternatively information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.”