A teenager who was king hit in Sydney's Kings Cross on the weekend has died in hospital.

Thomas Kelly, 18, was assaulted by an unknown man as he walked south along Victoria Street in the nightclub district just after 10pm (AEST) on Saturday

Mr Kelly, who was talking on his phone at the time of the unprovoked attack, collapsed to the ground.

The offender fled the scene while the teenager was rushed to hospital in a critical condition with head injuries.

He died late on Monday after his life support was switched off, police said.

They have launched a homicide investigation and detectives and Mr Kelly's parents will make a public appeal for assistance later on Tuesday.

Source:

http://news.ninemsn.com.au/national/8496845/teen-dies-after-kings-cross-assault