At first glance, these weapons would seem intended for use in the United States. Most likely, however, they were destined to cross the Rio Grande into Nuevo Laredo, where rival Mexican drug cartels are fighting for control.

Officials said the seizure occurred during a series of three raids conducted in January by the Department of Homeland Security's Border Enforcement and Security Task Force (BEST), a team comprising agents from ICE, the FBI, the Bureau of Alcohol, Tobacco and Firearms, and the Laredo Police Department.

Best, which is charged with stemming the flow of drugs and weapons back and forth across the border, has seized numerous other caches of weapons, cash and drugs in and around Laredo since October 2005. The success of the task force has prompted Homeland Security to create similar forces in other sectors of the border, and after it assesses the threat in Arizona, it will set up a task force there.

The material seized in the January raids is the type often used in urban warfare, which indicates the growing scope of violence on the border -- and the potential for more. In some cases, rival gangs have fought battles in Nuevo Laredo using heavy machine guns, assault rifles and even rocket-propelled grenades. Mexican laws make it more difficult and more costly to acquire weapons inside the country, as opposed to getting them from the United States. Obtaining illegal drugs in Mexico, however, is another matter entirely. Using contacts in the United States, then, the Mexican gangs smuggle narcotics across the border and bring weapons back into Mexico.

These drug gangs could be acquiring weapons from contacts in drug rings operating on U.S. military bases near the border. Ongoing operations in Iraq, Afghanistan and elsewhere have made fighting drug use by soldiers a lower priority within the military. In addition, the constant flow of materiel back and forth between the United States and combat theaters has made it increasingly difficult to account for every piece of ordnance. With pressure to recruit more troops, standards have been lowered, which has opened the door to recruits with prior drug convictions. The Mexican gangs, then, could be involving in-house dealers in weapons-for-drugs schemes.

Laredo is increasingly becoming a sanctuary for members of Mexico's various drug cartels. Nuevo Laredo drug gangs use Texas the same way the Taliban and al Qaeda use Pakistan: as a refuge from the fighting; a place where they -- theoretically -- can rest, regroup and plan further operations. The gangs also use Laredo as a transshipment point for drugs going north and weapons coming south, as evidenced by the BEST seizure.

In Afghanistan, however, the fighters seeking refuge on the Pakistani side of the border are on the same side, with a common enemy in the U.S.-led coalition and Afghan government. In Laredo, those supposedly seeking refuge represent competing cartels, and they are bringing their fight with them across the border. As a result, violent crime is increasing in Laredo as well.

The Mexican government's efforts to contain the drug wars and related violence in Nuevo Laredo have failed. On Feb. 6, for example, two gunmen attacked the headquarters of Nuevo Laredo's El Mañana newspaper, purportedly as a warning against publicizing the gang's activities. One reporter was injured.

With the continuation of the gang wars in Mexico, and Laredo's new status a sanctuary for rival gang members, the United States and Mexico will have to cooperate if they hope to reverse the escalation of violence on both sides of the border.