Hundreds of soldiers and federal agents were raiding casinos in Monterrey, Mexican authorities said, two days after an arson attack on a gambling house killed 52 people and stunned a country that had become numb to massacres and beheadings.
Security forces had so far confiscated about 1,500 slot machines at 11 casinos in Monterrey and its surroundings and arrested three people, Mexico's tax agency said. It said the continuing operation was meant to verify whether casinos had paid taxes or introduced slot machines illegally.
Thursday's arson attack by gunmen was a macabre milestone in a conflict that the government says has claimed more than 35,000 lives since President Felipe Calderon launched an offensive against drug cartels in late 2006. Others put the death toll near 40,000.
The torching of the Casino Royale has raised questions over Mexico's regulatory controls for fast-spreading gambling houses. Authorities have not been able to reach the owners of two companies pointed out as title-holders of the casino.
Jorge Domene, security spokesman for Nuevo Leon state, said an order to appear before state police has been issued for owners of the two companies, CYMSA Corp and Vallarta Attractions and Emotions.
Casino Royale's legal representative, Juan Gomez, told reporters that the shareholders of the business were Jorge Alberto and Raul Rocha Cantu. They will meet with police when authorities set the time, Mr Gomez said. Their family members have been prohibited from leaving the city, he said without offering details.
During the raids, which began on Friday, about 700 soldiers, federal police and Treasury Department agents seized slot machines and put them in moving vans.
Authorities did not say the raids were related to the arson. But one of the casinos searched was also registered under Vallarta Attractions and Emotions, according to the gaming unit of Mexico's Interior Department. Information of the other locations was not immediately available.
Federal police deployed 1,500 officers and sent Black Hawk helicopters to the state to step up security in the industrial metropolis of more than four million people. The Mexican army said it was sending in 1,500 soldiers.
Mayor Fernando Larrazabal said the Casino Royale and other 12 casinos violated municipal laws and were allowed to remain open after obtaining federal court injunctions.