A Texas state police helicopter opened fire on a truckload of fleeing immigrants Thursday, killing two and wounding at least one other.

The deadly incident took place near La Joya, Texas, about 70 miles northwest of Brownsville. State authorities reported that it began when Texas Parks and Wildlife police began pursuing a red pickup truck packed with immigrant workers, who were suspected of having crossed the border from Mexico.

When the pickup failed to stop for the game wardens, they called in the Texas Department of Public Safety, which sent the helicopter. DPS helicopters patrolling the border area carry snipers armed with high-powered rifles.

A spokesperson for the DPS, also known as the Texas Rangers, initially called the shooting an “enforcement action,” but declined to comment further on the killings. On Friday, the agency issued a statement claiming that the police had fired on the vehicle in an attempt to disable it.

The DPS added that the vehicle was traveling at “reckless speeds” and appeared to be a carrying a “typical covered drug load.” After the killings and the recovery of the truck, however, no drugs were found.

The regulations governing the Texas Rangers allow them to fire on vehicles carrying fleeing suspects, a procedure that is formally banned by most law enforcement agencies in the state and nationally. As Thursday’s incident demonstrated, the Rangers’ rules of engagement have turned the border into a combat zone.

Eight passengers of the vehicle were arrested after the shooting. Seven of them were from Guatemala. A Guatemalan government official expressed shock over the incident.

“This incident surprises us because we had never seen force being used from a helicopter... What had happened in the past were car pursuits and, in some cases, the shooting of undocumented persons,” said Rita Claverie, Guatemala’s deputy minister of foreign relations.

Since 2007, the Texas state government headed by Republican Governor Rick Perry has poured some $600 million into what it has dubbed Operation Border Star, an effort to deploy militarized state and local police units along the border.

In addition to the armed helicopters, the Texas Rangers have deployed six armored high-speed gunboats on the Rio Grande River. Each of them is mounted with six .30-caliber fully automatic machine guns capable of firing 900 rounds a minute on the Rio Grande River.

The state also recently purchased a $7.4 million high-altitude spy plane equipped with high-resolution cameras and thermal-imaging capabilities.

Also operating on the border are Ranger Reconnaissance Teams, uniformed in combat fatigues and carrying assault rifles. Other funding has gone to pay overtime to local sheriff’s and police departments to deploy more cops on the border.

The Texas police measures that claimed the lives of two unarmed immigrants Thursday are part of a broader militarization of the 2,000-mile-long US-Mexican border that has produced steadily escalating brutality and death.

In addition to the latest killings in Texas, there have been at least four other unarmed people shot to death by federal agents in the border area just since July.

The most recent, the October 10 killing of 16-year-old Jose Antonio Elena Rodriguez by Border Patrol agents shooting through the border fence from Nogales, Arizona, prompted outrage in Mexico and a condemnation by the United Nations human rights division.

“There have been very many young people, teenagers, who have been killed at the border,” Navi Pillay, the UN High Commissioner for Human Rights, told a news conference in Geneva last week. “The reports reaching me are that there has been excessive use of force by the US border patrols while they are enforcing the immigration laws.”

The Border Patrol claimed that its agents fired on the 16-year-old as he and others were throwing rocks at them, a form of deadly retaliation that the agency finds legitimate. Witnesses in Nogales said that the youth’s body was riddled with bullets and that he had been shot in the back.

The shooting of Elena Rodriguez came just a week after another incident in which Border Patrol agent Nicholas Ivie was shot to death on October 2 in southern Arizona. Arizona’s Governor Jan Brewer and other right-wing anti-immigrant politicians seized upon the shooting to demand a greater crackdown to secure the border.

An investigation, however, established that Ivie was the victim of “friendly fire” resulting from the militarized atmosphere that already exists. Having gone to check a tripped ground sensor, he saw someone approaching and fired. The person approaching was another Border Patrol agent who returned fire, killing Ivie.

Since 2010, at least 18 people have been killed by the Border Patrol. In other recent incidents:

• Valeria “Munique” Tachiquin Alvarado, a 32-year-old mother of five and a US citizen, was shot to death on September 28 by Border Patrol agents who came upon her while searching for an undocumented immigrant in Chula Vista, California. The Border Patrol claimed that its agent fired through Alvarado’s windshield after she struck him with her car and drove away as he clung to her hood. But witnesses said the agent fired while standing in front of the car, which some insisted was backing away from him. The agent has been identified as Justin Tackett, who was hired by the Border Patrol after being forced out of the Imperial County Sheriff’s Department, which described him as “a person who cannot be trusted with a badge or a gun.”
• On September 3, Border Patrol agents in a patrol boat shot and killed Guillermo Arevalo Pedroza, a 36-year-old Mexican bricklayer, who was celebrating his wife’s birthday with a cookout by the Rio Bravo in Nuevo Laredo, Mexico, just south of Laredo, Texas. Again the agents said someone had thrown rocks at them, a claim that witnesses denied.
• On July 8, Juan Pablo Perez-Santillan, 30, was shot while standing on the Mexican side of the border across the Rio Grande from Brownsville, Texas. A lawsuit filed by the family against the US government recounts that Santillan was shot by an agent with a long-range rifle as he was showing a group of immigrants how to swim across the river. When his brother cried out for help, one of the agents replied in Spanish “let the dog die.”

The legal complaint argues: “This heinous act was apparently also the result of the ‘corporate culture’ or general mentality of the US Border Patrol—which the United States of America and its agencies have allowed to develop and go unchecked—regarding its unofficial ‘open season’ policy concerning the use of excessive and deadly force against Mexicans and other Latinos in the area of the Mexican-American border.”

Since 2004, Washington has doubled the number of Border Patrol agents to over 20,000, even as the rate of immigration has slowed substantially following the financial crisis of 2008 and the fall in employment in the US.