Fifty-three people are dead and a dozen more injured after several gunmen burst into a Monterrey, Mexico casino, doused it in gasoline and lit it on fire. Witnesses said armed men told gamblers and employees to leave while they poured gasoline. Many, however, retreated further into the building out of fear, trapping themselves as the flames spread. “This is a sad night for Mexico,” said federal security spokesman Alejandro Poire in a televised address. President Felipe Calderon released a statement on Twitter, calling the incident “an abhorrent act of terror and barbarism.” Monterrey has been the scene of increasing violence as the Zetas and Gulf drug cartels battle for territory in the area. Attorney General Leon Adrian de a Garza said one of the gangs was responsible for the casino attack. The cartels often extort businesses by threatening to attack them or burn them to the ground if they refuse to make payments. In May, the same casino was sprayed with bullets by armed gunmen, but no one was injured. Monterrey’s murder rate has risen precipitously in the past two years. At this rate, killings in 2011 will be double what they were last year.