Two men have been charged over an assault in Fortitude Valley on Sunday morning that left an 18-year-old man fighting for his life in hospital.

A Queensland Police spokeswoman confirmed the men, both aged 21, had been charged with one count each of causing grievous bodily harm.

The men, one from Coombabah and one from Tanah Merah, are expected to face Brisbane Magistrate's Court on Monday morning.

Earlier on Sunday a team of detectives was scouring CCTV footage in a bid to identify up to four men they believed to be responsible for the attack.