SASABE, Mexico (By Olga R. Rodriguez, AP) May 1, 2007 — Mexican drug lords are taking over the business of smuggling immigrants into the United States, using them as human decoys to stop authorities from capturing cocaine shipments.

U.S. and Mexican law enforcement officials said that drug traffickers, in response to a U.S. border crackdown, have seized control of the routes they once shared with human smugglers.

The drug gangs get protection money from the immigrants and then effectively use them to clear the trail for the flow of drugs.

Illegal immigrants are used ''to maneuver where they want us or don't want us to be,'' said Alonzo Pena of U.S. Immigration and Customs Enforcement.

Gustavo Soto of the U.S. Border Patrol said smugglers are carrying drugs along paths once used primarily by immigrants. New fences and National Guard troops have helped seal the usual drug routes, and vehicle barriers are forcing traffickers to send more drugs north on the backs of cartel foot soldiers, he said.

''We have been able to seal many of the drug routes by adding technology and more agents,'' Soto said. ''We're seeing a tremendous amount of drugs being seized.''

The advent of drug-trafficking extortionists along the border may also be responsible for much of the drop in illegal immigration that U.S. officials have attributed more directly to better enforcement.

At times, the immigrants are pooled and sent across in large numbers at one time of the day, clearing the route for a drug shipment a short time later. Smugglers also direct immigrants away from successful drug routes in hopes of minimizing the manpower U.S. authorities assign to the area.

''The drug traffickers won't allow migrants to enter because the area will 'heat up' and the U.S. Border Patrol will be on alert,'' one local Mexican official said, speaking on condition of anonymity for fear of retribution. ''They want control so they can 'cool off' the area and go in with their cargo.''