(CNN) -- Thirteen people were shot outside a nightclub in Tempe, Arizona, police said Saturday.
No fatalities had been reported from the shooting, which occurred late Friday, but two people were in serious condition, Sgt. Steven Carbajal said.
Police were searching for two men who left the scene.
Concertgoers were outside The Clubhouse nightclub to hear rapper Nipsey Hussle perform.
One patron said she was backed up against a wall and people were losing their phones in the panic during the shooting.
The witness, who described the scene via Twitter under the moniker @RenTen10, wrote that she was struck by how many abandoned high-heeled shoes were on the pavement and sidewalk after the incident.
Nipsey Hussle, who didn't go on stage, used his Twitter account to express his displeasure with the shooting at his show.
"(Arizona) ... y'all gotta be cool man," he wrote.
CNN's Mariano Castillo and Maria P. White contributed to this report.