Drugs linked with illegal immigration?

It's dangerous enough to enter the United States illegally through the Arizona desert. Temperatures can top 100 degrees Migrants often don't carry enough water to remain hydrated for the days-long hike. And unscrupulous smugglers have been known to abandon their charges if they've already paid the crossing fee.

Now, imagine doing it high on amphetamines.

Border Patrol agents say that's happening more and more, as hapless border crossers find themselves entangled with drug smugglers looking for a way to get their product into the country. In exchange for carrying drugs across the border, the smugglers called "narcotraficantes" or "polleros" cover some of what the immigrants pay to their guides. The crossers then take a pill typically speed so they'll have enough energy to make it to the drop site.

"The drugs are just as fatal for the immigrants as their trek through the desert," said Hector Salazar of Grupo Beta, a rescue group created by the Mexican government to help stranded migrants near the U.S. border. "The polleros need them awake to make the crossing."

Most illegal drugs enter the United States at the southern border, where millions of people cross through 25 ports of entry each day, said Anthony Placido, the Drug Enforcement Administration's acting assistant administrator for intelligence.

Though the vastness of the region and the huge volume of border traffic complicate the enforcement picture, official corruption in Mexico remains the largest impediment to slowing drug traffic from that country, he said.

"In actuality, law enforcement in Mexico is all too often part of the problem rather than part of the solution," Placido told a House committee earlier this year. "This is particularly true at the municipal and state levels of government."

Even the Mexican prison system contributes to the problem. Major drug lords have been incarcerated, but they are able to continue running their businesses from their cells, Placido said.

At the northern border, the problem is less acute. Better coordination between the Border Patrol and Canadian authorities helps, said Joseph Giuliano, deputy chief patrol agent for the Blaine, Wash., sector.

Also, the forbidding landscape makes it harder for smugglers to come across. According to the DEA, drugs are ferried in both directions via all modes of transport: cars, backpacks, all-terrain vehicles, even snowmobiles.

But the importation of drugs from Canada is a growing threat, mostly because of links between Asian organized crime and groups in Canada, Placido said. While drugs such as heroin were previously sent from Southeast Asia directly to New York, the DEA now believes more is being smuggled through such cities as Toronto and Montreal.