Marines arrested 19 suspected members of the Los Zetas drug cartel, including seven minors, at a training camp for gunmen in the northern Mexican state of Nuevo Leon, the Navy Secretariat said.
Marines aboard three UH 60 Black Hawk helicopters spotted the training camp at a ranch near the Monterrey-Colombia highway in the northern part of Nuevo Leon.
The marines dropped into the ranch by rope from the helicopters and captured the suspected gunmen.
Four rifles, 26 ammunition clips, 1,457 rounds of ammunition, military uniforms and combat boots were seized in the operation, the secretariat said.
Monterrey, Mexico's most important industrial city, and its suburbs have been battered by a wave of drug-related violence since March 2010, when three rival cartels reportedly went to war with Los Zetas, considered the country's most violent criminal organization.
Los Zetas has been battling an alliance of the Gulf, Sinaloa and La Familia drug cartels, known as the Nueva Federacion, for control of the Monterrey metropolitan area and smuggling routes into the United States.
The most brutal incident in the turf war occurred on Aug. 25, when suspected Zetas gunmen set fire to Monterrey's Casino Royale, killing at least 52 gamblers and employees trapped inside, most of whom died of smoke inhalation.
Heriberto Lazcano Lazcano, known as "El Lazca," deserted from the Mexican army in 1999 and formed Los Zetas with three other soldiers, all members of an elite special operations unit, becoming the armed wing of the Gulf drug cartel.
After several years on the payroll of the Gulf cartel, Los Zetas, considered Mexico's most violent criminal organization, went into the drug business on their own account and now control several lucrative territories.