(CNN) -- Gunmen opened fire at an illegal cockfighting ring in southern Texas early Thursday morning, killing three people and wounding at least eight, the Hidalgo County sheriff's office told CNN.
Sheriff Lupe Trevino told CNN affiliate KRGV that his deputies are "dealing with a crime scene from hell."
The injured were taken to hospitals in the area, sheriff's communication supervisor Gloria Felix told CNN.
The site, a ranch near the city of Elsa, hosted a sophisticated cockfighting operation complete with concession stands and bleachers, the sheriff told KRGV.
Several masked gunmen opened fire, and people took off running into the brush, he said.
Deputies were looking for witnesses and evidence. No arrests had been made as of Thursday morning.
Elsa is close to the Mexican border in the Rio Grande Valley, near McAllen.
CNN's Scott Thompson contributed to this report.