Updated

Hundreds of protesters demonstrated Sunday against the government in the aftermath of a casino arson attack that killed 52 people and has been labeled one of the worst crimes of Mexico's deadly five-year drug war.

Clad in the white shirts that have been adopted at Mexican demonstrations against violence and crime, more than 1,000 people demanded that the Nuevo Leon state governor and the mayor of the industrial city of Monterrey quit.

Demonstrators held protest signs against the political leaders. They said they are tired of the violence that afflicts the metropolis of 4 million as the Gulf drug cartel and the rival Zetas battle over turf.

The protest came as the website of the newspaper Reforma reported that state police arrested two people in connection with Thursday's attack on the Casino Royale. The newspaper quoted a state official, who did not answer phone calls seeking confirmation.

Other officials, including Nuevo Leon Gov. Rodrigo Medina, refused to confirm or deny the arrests.

A surveillance tape of Thursday's fire shows eight or nine men arriving in four cars carrying canisters into the Casino Royale on a commercial avenue. In little more than two minutes, the casino is in flames and choking black smoke churns from the building.

Authorities released sketches of three of the men based on interview with survivors of the fire. The newspaper report gave no information on what role the detained men allegedly had in the attack.

According to witnesses, the gunmen burst into the casino and shouted for people to get out, saying they were burning the place down. But people ran farther inside the building, where many were found dead from smoke inhalation in offices and bathrooms.

President Felipe Calderon has offered a $2.4 million reward for information leading to the capture of the casino's attackers, an amount comparable to the ones offered for the arrest of the country's top drug lords.

In a country that has grown used to beheadings and grisly mass killings in the drug war, the casino attack shocked Mexicans because most of the victims were middle class women who frequented the casino with friends.

The government says more than 35,000 people have been killed in drug-related violence since President Felipe Calderon launched an offensive against drug gangs in late 2006. Others put the death toll near 40,000.

After the casino fire, federal and local authorities have set their eyes on the increasing number of gambling houses that are violating laws.

About 700 soldiers, federal police and Treasury Department agents raided eight Monterrey casinos Friday and Saturday, confiscating more than 3,500 slot machines that did not meet Mexico standards. They also arrested three men, whose names were not made public, with two guns and a grenade.

The head of the Mexico's tax agency, Alfredo Gutierrez, said at a news conference Sunday that the raids were not related to the arson attack.