Police found what appear to be the remains of six men at a site in this northern Mexican metropolis where a criminal organization burned victims' bodies, authorities said.

The discovery stemmed from the investigation of last week's arson attack at a Monterrey casino, which claimed 52 lives.

Five suspected members of the Los Zetas drug cartel arrested for starting the blaze at the Casino Royale revealed the existence of the clandestine crematorium under interrogation by police, a spokesperson for the Nuevo Leon State Security Council said.

Besides the human remains, police who inspected the site found plastic containers of fuel, indicating that the criminals "cooked bodies" there, the spokesperson said.

In another development related to the Casino Royale atrocity, federal authorities and municipal inspectors shut down three other Monterrey casinos that were operating without licenses.

Army troops and police escorted the officials who delivered the orders closing the Yak Electronico, Royal Yak and Winland establishments.

The Casino Royale was also unlicensed, but remained in business thanks to the intervention of an administrative judge who resigned after last week's fire.