Armed Mexican government personnel made unauthorized incursions into the United States five times in the last three months of 2005, including one incident last month in Southern California, according to confidential Department of Homeland Security records.
The crossings involved police officers or soldiers in military vehicles and were among 231 such incidents recorded by the U.S. Border Patrol in the last 10 years.
The records obtained by The Times provide new details on more than a dozen incursions into the U.S., including the five most recent ones.
Details of the incidents emerged as authorities on both sides of the border scrambled to investigate a dangerous confrontation Monday in Texas.
Heavily armed personnel in a military-style Humvee from Mexico helped drug smugglers fleeing police to escape back across the border, according to authorities. An internal Border Patrol summary of the incident said the Humvee was equipped with a .50-caliber machine gun.
It was the second such incident in three months in the same rural county southeast of El Paso.
"It's clear you're dealing with a large number of incursions by bona-fide Mexican military units, based on the tactics and the equipment being used," said T.J. Bonner, a Border Patrol veteran and president of the agents union.
Reports of incursions into the U.S. by gun-toting groups of men dressed in what appeared to be military or police uniforms along the Mexican frontier have become a powerful rallying point for advocates of illegal immigration crackdowns and tighter border security.
The incursions have also intensified a long-running debate over the merits of fencing the 2,000-mile Mexican border, now a patchwork of metal barriers, rusted and broken barbed wire and expanses of rugged terrain where the divide is difficult to identify. In Texas, the Rio Grande separates the two nations.
U.S. Border Patrol Chief David V. Aguilar said that incursions by Mexican government personnel were nothing new, and that U.S. agents on occasion have crossed accidentally into Mexico. He noted that incursions have declined by more than 50% since 2002. Still, with assault rates against agents at record highs, any incursion is taken "very seriously."
"These are not taken lightly at any level within the Border Patrol
U.S. Sen. Jon Kyl (R-Ariz.) said in an interview Wednesday that this week's incident in Texas was "about as serious as it gets" and noted that dozens of reported incursions have occurred in his state.
The encounters seriously undermine efforts to stop the flow of drugs coming across the U.S. border and suggest possible cooperation among Mexican authorities and traffickers, he said.
"You do not want to get into a fight with guys carrying machine guns," said Kyl, chairman of the Senate Judiciary Subcommittee on Terrorism, Technology and Homeland Security.
He has asked the State Department to investigate the incursions and said that he plans to hold a hearing on the issue in March. Rep. Tom Tancredo (R-Colo.), a leading anti-illegal immigration lawmaker, called this week for U.S. troops to be deployed along the border to counter armed incursions.
Mexican officials on Wednesday denied that their police and military have been involved in illicit crossings but said they are investigating Monday's incident.
In recent interviews, local and federal law enforcement officials in south Texas and the San Diego area said a long pattern of encounters with Mexican government units along the border have bolstered suspicions that their counterparts work with smugglers. In Laredo, Texas, authorities said they have repeatedly seen Mexican military units clearing people from brushy areas along the south banks of the Rio Grande shortly before loads of migrants and drugs are brought across.
Several of the incidents described in the Department of Homeland Security reports appeared to involve Mexican officials getting lost or pursuing suspects. For example, five Tijuana police officers pursued two men across the border in 2004. Some of the officers fired at the suspects while on U.S. soil, according to a Border Patrol report. The police returned to Mexico after arresting the men.
Other encounters were more suspicious and add to concerns among many U.S. law enforcement officials that corruption in Mexico is eroding efforts to gain control of the border and combat trafficking in humans and drugs.
In October, Border Patrol agents in the El Cajon area east of San Diego reported seeing Humvees on the south side of the border fence. Minutes later, they saw two men in Mexican military uniforms carrying rifles in a creek bed north of the border, according to the records. When an agent approached, the two men ran south and drove off in the Humvees. Agents found footprints indicating three or four individuals had come north of the border and then returned.