A prison riot between rival gangs left nine inmates dead and 20 more wounded, Venezuelan media said Saturday. The fighting began Friday morning when gunfire broke out in the San Fernando de Apure lockup in central Venezuela, according to the Caracas-based El Nacional newspaper. The uprising was controlled with the help of more than 100 national guard and police agents, it said. Like in many other countries in the region, violence is common in Venezuela's overcrowded and understaffed prisons. Of the country's nearly 20,000 inmates, 500 were killed and more than 1,000 wounded last year in riots and other violence, according to the Venezuelan Observatory of Prisons watchdog group.