Officers believed the suspect was barricaded in an apartment building at Oxnard Street and Laurel Canyon Boulevard near the 170 Freeway.
Residents in the apartment complex and the immediate area had to be evacuated.
It started around 10 p.m. Sunday when officers responded to a call of multiple shots fired.
When officers arrived on scene, they found one man in his 20s with a gunshot wound. He was transported to a local hospital, where he was listed in stable condition. Police recovered one firearm.
Officials said there were at least two gunmen shooting at each other. They believed the suspects were still in the area and deployed their K-9 units, which led them to the small apartment complex on Laurel Canyon Boulevard.
After several hours, the SWAT operation was called off with no suspect in custody.
The incident remained under investigation.