Fighting between feuding drug-cartel rivals appears to have killed at least 44 and as many as 70 inmates in an overcrowded Mexican prison, an official said. The prisoners from the powerful Zetas drug cartel, one of Mexico\'s most brutal cartels, and the rival Gulf cartel, Mexico\'s oldest organized-crime group, died when 750 inmates from one cell block invaded another cell block of 750 in a prison in Apodaca, near the city of Monterrey, Nuevo Leon state public security spokesman Jorge Domene Zambrano told Mexican newspaper El Universal. Monterrey is Mexico\'s industrial capital. The riot started at 2 a.m. Sunday and lasted several hours before state and federal police could bring the prison under control, Domene told The New York Times. Domene put the death toll at 44, but the Blog del Narco, a Web site that documents the Mexican drug war, cited sources as saying it was actually at least 70. The dead were stabbed, beaten and hit with stones, Domene said. Some prisoners were tied up and burned alive, the Blog del Narco reported. At least 120 people were injured, with some victims not receiving medical attention, the blog said. No firearms were found among the prisoners, Domene told The Wall Street Journal. The prison was built to house some 1,700 inmates but was jammed full with some 2,700 prisoners, he told the Journal. The entire prison staff on duty at the time of the riot, including the prison\'s director, has been detained to find out if 17 on-duty prison guards were involved in the fighting, he said. The Zetas and Gulf cartels, once the same organization, are normally securely separated, he said. Their rupture in 2010 led to a bloody turf war, predominantly in the states of Nuevo Leon and Tamaulipas, which borders Texas. Sunday\'s riot was the deadliest in a series of prison riots in northeast Mexico, including one last month in the Gulf coast city of Altamira in Tamaulipas in which 31 prisoners were killed and another riot in the Tamaulipas city of Matamoros, across the border from Brownsville, Texas, in October that killed 20. The latest riot came four days after a fire at an overcrowded penitentiary in Comayagua, Honduras, killed at least 382 people. It was the world\'s deadliest prison fire. The second-most-deadly was at the now-closed Ohio Penitentiary in Columbus on April 21, 1930, which killed 322. Among the dead in the Honduras fire were inmate spouses, Honduran newspaper El Heraldo reported.