Mexican authorities on May 1 announced the seizure of a ship carrying 68,000 tons of illegal iron ore bound for China -- hailed as the latest blow in a crackdown on the contradband mineral sideline by the Knights Templar drug cartel.

Federal police were apparently tipped off by an anonymous phone call after the ship left Lazaro Cárdenas, the Pacific port in conflicted Michoacán state. Authorities detained the ship, the Jian Hua, off Manzanillo, the next major port up the coast, in neighboring Colima state. The ship's crew produced documents showing it had authorization to transport the iron ore. But authorities said the paperwork listed a legal mine that was not the actual source of the contraband ore. The company operating the ship, China's Fujian Huarong Marine, has been given one month to prove to authorities that the ore was extracted legally. Mexican authorities say they have seized more than 200,000 tons of illegal iron ore so far this year, most of it headed for China

Two days before the seizure was announced, the mayor of Lazaro Cárdenas, Arquímedes Oseguera Solorio, was arrested along with the city treasurer and other officials by Mexican federal police on suspicion of ties to the Knights Templar. Oseguera is charged with extortion and illegal deprivation of freedom, with more charges pending as an investigation is underway. Lazaro Cárdenas has emerged as the main export hub for the Knights Templar, believed to be one of the main suppliers of methamphetamines to the United States.