Man stabbed in Brisbane brawl

A man has been stabbed during an overnight brawl involving up to 20 people in Brisbane's Fortitude Valley.

The 19-year-old was treated for a wound to the abdomen in Royal Brisbane Hospital, while another man who received a cut to his mouth was also taken to hospital, police say.

Detectives are examining CCTV footage of the fight, which broke out about 2.15am on Thursday.