By Richard A. Serrano and Tracy Wilkinson, Tribune Washington Bureau

WASHINGTON — Two heavily armed, camouflaged Mexican soldiers crossed 50 yards inside Arizona in January and drew their guns against U.S. Border Patrol agents who confronted them in a tense standoff, according to documents obtained by the Los Angeles Times and Tribune Washington Bureau.

U.S. officials said it was one of nearly two dozen border incursions by Mexican soldiers into southern Arizona in the last four years.

The Jan. 26 confrontation, described in a Border Patrol foreign military incursion report and confirmed in a separate letter from U.S. Customs and Border Protection Commissioner R. Gil Kerlikowske, ended when the Mexican soldiers retreated back over the border after U.S. agents — who also drew their weapons — summoned assistance. The soldiers, who misidentified themselves to border agents, claimed to be pursuing drug smugglers, documents show.

U.S. officials characterized the incident as one of the most serious incursions in recent years. Though gunfire was averted, the 35-minute confrontation underscored the continuing friction between the U.S. and Mexico when it comes to policing the often chaotic and violent Southwest border. It also raised questions among some U.S. officials about whether the Mexican soldiers were chasing drug smugglers, as they claimed, or protecting cartels as they used drug routes to Arizona.

Early Tuesday, officials at the Mexican Embassy in Washington — as they had for the last two weeks — denied that Mexican soldiers were involved, suggesting that the men were smugglers in military uniforms. But when presented with the U.S. confirmation of the incident, the embassy later called a Times/Tribune reporter and confirmed that the men were soldiers.

“Those individuals were part of a counternarcotics operation, which had taken place a few minutes prior on the Mexican side of the border,” said Ariel Moutsatsos, minister for press and public affairs at the Mexican Embassy. “The two members of the Mexican army did not see any sign notifying them that they were crossing the border.”

He called the incident “an isolated and unintended occurrence.” He noted that U.S. border agents also crossed the border from time to time.

“Both U.S. and Mexican agents have sporadically and accidentally crossed our common border during their patrols,” he said. “Both countries understand that this is something that happens as part of normal activities.”

Eduardo Sanchez, a spokesman for President Enrique Pena Nieto’s security Cabinet, confirmed the January incident and said the Mexican soldiers spotted what they believed to be men carrying backpacks with drugs. They pursued the men and recovered the backpacks, only to find themselves on the U.S. side of the border.

“It’s desert there, there are no fences, no walls,” Sanchez said in explaining how the soldiers could have crossed unawares. He said the error was realized within minutes, and the soldiers returned. Their commanders spoke to U.S. officials in Tucson to explain, and it was chalked up as an error.

Kerlikowske, in his letter to Sen. Tom Coburn (R-OK), the ranking Republican on the Senate Homeland Security and Governmental Affairs Committee, said military incursions from Mexico were infrequent. But his letter cited 23 such incidents in the Tucson and Yuma sectors of Arizona since 2010, including three in this fiscal year.

The January incursion was reported the same day to the commissioner’s situation room and generated a “significant incident report.” But U.S. border officials deemed that no further action was necessary, Kerlikowske wrote.

Nevertheless, disclosure of the incursion is likely to cause border advocates such as Sen. John McCain (R-AZ), and others to demand a stronger U.S. defense along the four states that constitute this side of the 1,000-mile U.S.-Mexico border.

In July 2011, the Mexican Defense Ministry confirmed that its soldiers had crossed into Texas over the Donna-Rio Bravo International Bridge. The crossing was unintentional and the soldiers were trying to find their way back into Mexico while on routine patrols, the ministry said. The U.S. Border Patrol apparently accepted the explanation.

The latest encounter began at 8:53 a.m., when Border Patrol Agent Justin Hays spotted “two subjects entering the United States approximately 2.5 miles west of the Sasabe (Ariz.) Port of Entry,” according to the report. Agent David Olaya responded to the area and reported seeing subjects who appeared to be Mexican military personnel about 50 yards north of the border.

At 9:20 a.m., Olaya said, he “positively identified the two individuals in tan, digital camouflage uniforms, on foot traveling westbound, on the United States side of the International Boundary Fence Line,” the report states.

Confronting them, “both parties drew their weapons,” the report said. The Mexican soldiers were carrying what was described as “G3 long arms” — an apparent reference to assault-style weapons — and identified themselves as members of the Mexican military’s 80th Battalion.

The report said the men identified themselves as Carlos Antique Juarez and Jorge Alberto Hernandez-Morales. But Olaya noted that the name tapes on their uniforms “did not coincide with the names provided. One, in fact, was partially covered.” Juarez’s name tag said “Diaz”; Hernandez-Morales’ tag showed only “Rue.”

The soldiers told U.S. agents that they had been pursuing three suspects from Mexico. But when Olaya called for backup from the Border Patrol’s Tucson sector, the two Mexicans retreated over the border.

In his letter, Kerlikowske noted that Border Patrol agents at that time had been actively pursuing three suspects in the isolated, rugged terrain, and had recovered three bundles of marijuana. But he said no arrests were made and the three subjects escaped.

Kerlikowske said the U.S. later determined that the two Mexican soldiers were “confirmed members of the Mexican military.”

In response to a question from Coburn about whether the soldiers might have been providing security to drug smugglers, Kerlikowske said his agency “does not have intelligence that directly connects (Mexican military) personnel to criminal activity.”

But border experts say that Mexican soldiers have frequently been hired to assist drug smugglers.

“It’s pretty easy to co-opt them,” said James Phelps, a border and homeland security professor at Angelo State University in San Angelo, Texas. “Many are essentially a functional asset of the cartels.”

He recalled an incident a few years ago in which a Mexican army captain was helping to transport a five-ton truck loaded with methamphetamine until he stopped just before reaching El Paso.

Photo by Steve Hillibrand via Wikimedia Commons