Gunmen stormed a crowded casino in northern Mexico on Thursday and ignited a fire that trapped patrons inside, killing at least 53 people in what the nation's president called an "aberrant act of terror."
The attack on the Casino Royale was the latest bout of spectacular violence in Monterrey, an industrial hub that is Mexico's third-largest city. For more than a year, the city has been the setting for a brutal turf war between rival drug-trafficking gangs that at times have held gunfights on downtown streets in broad daylight.
Adrian de la Garza, prosecutor for the border state of Nuevo Leon, told reporters that the death toll stood at about 40. Four people remained missing. Gov. Rodrigo Medina later told Mexican media that 53 had died.
He said the five or six attackers apparently used gasoline to start the blaze. Officials did not give a suspected motive.
Mexican President Felipe Calderon went on Twitter to express dismay over what he called an "aberrant act of terror and barbarity."
"This is a night of sadness for Mexico," said Alejandro Poire, a federal security spokesman. "An unspeakable, repugnant, unacceptable act of terror has been committed."
Television images showed shocked patrons waiting outside as helmeted rescue workers raced into the blackened casino in search of survivors.
One woman told Milenio Television that customers scattered in panic after profanity-spewing gunmen burst into the casino and ordered people to get out. In the confusion, many people trapped themselves inside after hiding in bathrooms or fleeing to an upper floor.
Emergency exits were blocked, possibly increasing the death toll, officials said.
Monterrey Mayor Fernando Larrazabal said the casino was shut down in May for code violations but later allowed to reopen after lawyers for the casino won a court order.
The woman interviewed by Milenio Television described a frenzied scene.
"Four armed persons entered and began to say: 'Everybody leave! Everybody leave!' " she said. The woman said she ran out a door to a parking lot, but many others fled to the second floor of the casino.
The witness said the attackers, wearing white masks, did not fire weapons or hurl grenades, as some early news reports had suggested. "They started to throw gasoline. There was no grenade attack," she said.
At least 20 people were killed in July after suspected drug cartel members opened fire in a crowded Monterrey bar, an apparent attack on a rival gang.
Much of northeastern Mexico has been besieged for a year and a half by fighting between the Gulf cartel and former allies known as the Zetas. The bloodshed has been especially shocking in Monterrey, an important business town formerly known for relative tranquillity.
Violence has exploded across Mexico since Calderon declared war on the cartels soon after taking office in 2006.
Cecilia Sanchez of The Times' Mexico City bureau contributed to this report.