CAMPO, Calif. (AP) _ Martin Facio can thank the U.S. government for reminding him of the proper way to dress when sneaking across the border.

Because of a U.S. border crackdown in the balmy San Diego area, illegal aliens have been trying to cross into the United States by trekking through the cold, windswept mountains to the east. As a result, at least 14 immigrants have died of exposure in the past month.

To prevent more deaths, the U.S. and Mexican governments are broadcasting public service announcements warning illegal immigrants to stay away from the area.

``Well, I'm not saying we should tell them how to get here, but sometimes we find them wearing trash bags they've found _ like that's going to keep them warm and dry,'' said Ronny Kastner, a Border Patrol agent in Campo, where an average of 125 immigrants are arrested each night. ``This year we found them after it was too late, or we found people real cold.''

Facio, a 33-year-old auto repairman from Mexico City, heard radios crackling in Tijuana with helpful hints for would-be crossers.

He and his nephews bought long underwear and flannel shirts and stayed in a Tijuana way station until the weather, which had been around the freezing mark, broke. As temperatures climbed to the mid-50s, Facio and his nephews set out on their journey, heading more than 50 miles east of Tijuana.

``I heard the warnings, but I don't care,'' Facio said from behind bars recently. ``In Mexico, there is no work.''

By the time Border Patrol agents caught them and put them in a detention cell just after nightfall on the same day they set out, the temperature had dipped to 38 degrees.

In the next 24 hours, 126 other immigrants were detained by agents based at Campo, an enforcment area that encompasses an Indian reservation, the Cleveland National Forest and the site of most of the 14 deaths _ the Laguna Mountains.

Although the international border and the main highway are only two miles apart, impassable mountains turn the trip into a 22-hour marathon. And that's if the aliens don't stop to rest or eat. The average illegal immigrant logs three to four days between the border fence and downtown Campo.

Several years ago, immigrants sneaking into Southern California crossed over from the booming city of Tijuana into San Diego, where even winter temperatures overnight are in the mid-40s and 50s.

It's a straight 20-minute sprint from the streets of Tijuana to the closest San Diego highway _ so easy that some teen-agers used to run back and forth between countries several times in one night just for kicks.

But a federal program called Operation Gatekeeper tightened up the border in urban San Diego. Launched in 1994, Operation Gatekeeper bolstered the U.S. side of the border with night-vision equipment and more than 600 additional Border Patrol agents.

To avoid the fortified region, illegal immigrants have shifted their crossings eastward to the more treacherous mountains where Border Patrol reinforcements are just now arriving. The results have been tragic.

Protected only by thin jackets, jeans and sneakers, some of the 14 victims had spent days walking through calf-high snow without food or water. With temperatures in the low 30s and a stinging wind in their faces, two other men were nearly delirious from cold and hunger when they approached Border Patrol agents, begging to be rescued. One was barefoot because his shoes had gotten lost as he stumbled up the mountain.

Facio and his nephews had less than $300 between them, so they heeded the public service announcements and used their money to buy warm clothes instead of hiring a smuggler who could help lead them across.

While Facio was disappointed the Border Patrol had caught him, the trip wasn't entirely worthless, he said: ``Next time I am going to wear gloves.''