The US Border Patrol is conducting an investigation into an incident on November 9 when agents trying to stop a drug smuggler near El Paso, Texas, crossed over the Rio Grande river, which forms the boundary with Mexico there. This is just the latest in a series of border crossings by both U.S. and Mexican law enforcement personnel.

The Border Patrol agents crossed about seven meters into Mexico while in hot pursuit of a drug smuggler. Mexican authorities in Guadalupe, Chihuahua, about 40 kilometers southeast of Ciudad Juarez, said local police confronted the US agents and that, while both sides had weapons drawn, no shots were fired.

Doug Mosier, spokesman for the U.S. Border Patrol in El Paso, says the agents crossed into Mexico by accident while engaged in a tense pursuit of an alleged drug smuggler in a pickup truck. "The agents attempted to stop the vehicle in the United States when it crossed illegally from Mexico. The smuggling vehicle failed to yield and the driver attempted to elude agents by crossing the Rio Grande, in returning to Mexico. The truck ultimately became stuck in the river. Agents entered the river in an attempt to secure the vehicle," he said.

He says the agents retrieved about 136 kilograms of marijuana from the river, but the suspect escaped. Mosier says this section of the border has been tense for some time. "We have had several occasions in that same vicinity, where we have had agents shot at and even one agent shot in the last couple of years in a very similar kind of scenario," he said.

Mosier says the incident has not resulted in a dispute with Mexican authorities because officers on both sides of the border understand the nature of dealing with criminals who try to evade arrest by crossing the border. He says there have been numerous crossings into the United States by Mexican authorities and into Mexico by U.S. agents, but both sides make an effort to coordinate and cooperate. "We do continue to share information and work jointly with our Mexican counterparts in efforts to make the border a safer place. This is done through joint, cooperative enforcement efforts aimed at reducing border violence, human trafficking and drug smuggling that occurs along this area of the border," he said.

According to the U.S. Department of Homeland Security, there have been 216 crossings into the United States by Mexican police and soldiers since 1996. Most of the incursions were considered inadvertent, but local police in the border region say they have seen what they describe as Mexican soldiers assisting drug traffickers to cross the river. There was a standoff between Hudspeth County, Texas, Sheriff's deputies and men from the Mexican side of the border dressed in military attire in January.

US officials have not said how many times U.S. Border Patrol agents have crossed into Mexico, nor have they provided information on how many agents were involved in this latest incident, which is still under investigation.