Three teenagers have been injured in a violent brawl in Sydney’s inner west.

Police were called to a park at Newtown, after reports of people fighting around 10pm Friday.

View photos Three teens were left injured. Source: 7 News More

When they arrived, they found an 18-year-old with a stab wound to his stomach, and a 17-year-old girl with a cut to her leg.

A 16-year-old boy had been punched, knocking him unconscious.

Police have been told around 20 people confronted the teenagers before the fight broke out.

View photos Police were told about 20 people had been fighting in the park. Source: 7 News More

Anyone with information on the incident is urged to contact Crime Stoppers on 1800 333 000 or use the online reporting page.