Mexican authorities have arrested two more suspects in an Aug. 25 arson attack on a casino that killed 52 people trapped inside, the Defense Secretariat said.

The federal Attorney General's Office had offered a reward of up to 15 million pesos ($1.1 million) for information leading to the capture of the two men, the secretariat said Wednesday in a statement without identifying them.

With these latest arrests, 17 of the 18 suspects the AG's office said in September it was seeking in connection with the massacre are now in custody.

Jose Alberto Loera Rodriguez was arrested early this month as one of the alleged masterminds of the attack on the Casino Royale, located in the northern industrial city of Monterrey.

The massacre was attributed to the Los Zetas cartel, which is regarded as Mexico's most violent criminal organization. Los Zetas gunmen torched the casino because the gaming establishment's owner refused to pay protection money.

The assailants told the people inside the casino to get out before setting fire to the building, but the emergency exits were closed. The majority of the 52 victims died from smoke inhalation, with only seven burning to death.

Founded by deserters from an elite special forces unit, Los Zetas began as the armed wing of the Gulf drug cartel, but ended that relationship in March 2010 to go into business for themselves.

Hundreds have died in the ensuing turf battles between the aggressive upstarts and the established drug trafficking organizations.