Ten years ago, the U.S. border with Mexico at San Diego was the main entryway for hundreds of thousands of illegal immigrants each year. People gathered along the Tijuana hills and canyons at dusk, waiting to cross the border to a better life in America.

Operation Gatekeeper, a controversial increase in border enforcement, was introduced about the same time under the Clinton administration to reduce the traffic and mayhem that took place along a 14-mile stretch of the international boundary.

But critics say it did much more than that.

Gatekeeper pushed people trying to cross the border illegally out of sight to the more dangerous mountains and deserts east of San Diego, where more than 3,000 human remains -- believed to be those of illegal immigrants -- have since been found.

"It is a great human cost that has been paid for sealing the first 14 miles of the border (from the Pacific Ocean east)," said Claudia Smith, an Oceanside attorney and director of the California Rural Legal Assistance's Border Project.

Smith has been one of the most outspoken critics of the border build-up. She and other immigrant rights advocates called for dissolving Gatekeeper during rallies, marches and forums in San Diego County and Tijuana last week.

Since 1994, Operation Gatekeeper has become a model for similar enforcement efforts in Texas and Arizona. In that time, the federal government more than tripled funding for the U.S. Immigration and Naturalization Service to $5.5 billion in fiscal year 2002, according to INS figures.

Most of the increase went to enforcement efforts such as Gatekeeper. It increased the number of U.S. Border Patrol agents from 980 to more than 2,200, paid for double and triple fencing along the border in San Diego County, introduced stadium lighting, installed heat and motion sensors on the ground, and purchased helicopters and all-terrain vehicles.

Immigration officials say Operation Gatekeeper helped reduce the number of attempted border crossings along the San Diego County line and this, in turn, reduced the number of arrests from 450,000 in 1994 to 110,000 in 2001. They point to similar results with Operation Hold the Line in El Paso, Texas, and Operation Safeguard in Tucson, Ariz.

Most immigration experts say the enforcement efforts have simply diverted the illegal immigrant traffic to other parts of the border.

The U.S. Border Patrol's own figures show that the overall number of people arrested while attempting to cross the border has increased by 68 percent -- from 980,000 in 1994 to 1.6 million in 2000. The number of those arrested are believed to be a fraction of those who succeed in making it through.

"It's a classic squeeze and bulge effect," Smith said.

Even those who advocate stricter immigration policies say these strategies have been ineffective; they are not part of a comprehensive plan that includes tightening controls inside the country, such as work-site enforcement.

"Nobody believed that the border (control measures) alone would do it," said Steven Camarota, director of research at the Center for Immigration Studies in Washington, D.C. "It's a teeny, tiny part of the equation."

Camarota said strong border-enforcement measures must be backed by checking Social Security numbers for those seeking jobs, by levying sanctions on employers who knowingly hire illegal immigrants and by encouraging local police departments to cooperate with immigration agents.

Immigration authorities, however, have focused their attention at the nation's borders. Increased pressure from employers and protests from pro-immigrant groups have led Congress and authorities to practically abandon work-site inspections, Camarota said.

More job opportunities and higher wages are the dominant reasons illegal immigrants risk their lives to cross the border, according to a recently released report by Wayne Cornelius, director of the Center for Comparative Immigration Studies at UC San Diego.

"If the current border enforcement strategy were succeeding, we should see a tighter labor market resulting from shortages … in those industries where employers have come to rely on them," Cornelius wrote. "None of these … labor market effects has materialized thus far."

Where Operation Gatekeeper has succeeded is in increasing the number of people who die in remote areas of the border, Smith and other critics said. They blame the strategy for the greater number of deaths from the heat, dehydration and hypothermia along remote migration routes.

Immigrant rights advocates said officials who developed these strategies wrongly assumed that illegal immigrants would not risk their lives by crossing the border illegally through mountains and deserts.

"When this all began, (INS officials) told Congress that immigration would spike after NAFTA (the North American Free Trade Agreement) because it would displace workers. Operation Gatekeeper was going to take care of that," Smith said.

Those assumptions did not prove true, said Enrique Morones, who heads a group of volunteers, called Border Angels, that places water bottles along the border for illegal immigrants to drink during their journey.

"People are dying at the border," Morones said.

Several groups are scheduled to meet today at 11:30 a.m. for a Catholic Mass on both sides of the border. They will gather at Border Field State Park in San Ysidro and a Tijuana beach, where a rusty metal divide sinks to the Pacific Ocean.

Contact staff writer Edward Sifuentes at (760) 740-5426 or esifuentes@nctimes.com.