U.S. Customs and Border Protection says it has flown drone aircraft over Mexico to help investigate drug gangs, and the practice has been going on for years.
Mexican authorities say the flights have been mainly along the border and have been carried out at the request of the Mexican government. In a statement, the country's National Security Council says the operations all have been done under the supervision of Mexican agencies, including the air force.
The council says Mexico always sets the objectives of the flights and the information to be gathered. It says the drones have boosted Mexico's "capabilities and technological superiority" in its fight against drug traffickers.
The U.S. border agency says the drones are used for specific operations and not routine surveillance. As an example, it says drones were used in the search for suspects in the 2009 murder of a U.S. border agent.
The flights represent an expansion of the U.S. role in Mexico's drug war. Americans also have been training Mexican soldiers and police and cooperating on other intelligence matters.
The drone operations were first reported by The New York Times.
