MEXICO CITY (AP) — A Mexican man said Monday that Mexico's quasi-military National Guard opened fire on his SUV in the border city of Nuevo Laredo, killing his pregnant 15-year-old girlfriend and a 54-year-old friend, and wounding two other people.

The killings come nearly two months after an army patrol shot to death five men in cartel-dominated Nuevo Laredo on Feb. 26. Four soldiers have been charged in that case, drawing more criticism for President Andrés Manuel López Obrador's push to give the military a greater law enforcement role.

According to a complaint filed Monday by the local nongovernmental organization the Human Rights Committee of Nuevo Laredo on behalf of the driver of the SUV and other victims, the deaths occurred Sunday on a highway in Nuevo Laredo, across the border from Laredo, Texas. The shooting killed the young woman and her unborn child. One woman, 24, remains hospitalized.

According to the complaint, which was addressed to López Obrador, the Interior and Defense ministers and governmental human rights commission, the driver noticed a National Guard patrol vehicle began to follow him.

The driver said the patrol vehicle suddenly opened fire, largely hitting those sitting in the rear of the SUV.

The man, Luís Rodríguez Santiago, said he swerved into the other lane of the highway to avoid the gunfire, lost control of the vehicle and it slammed into a lane barrier.

Wounded himself, Rodríguez Santiago said he tried to reach his wounded, pregnant girlfriend.

"The soldiers shouted at me, 'Get back, get back ... or we'll kill you," according to the complaint. "Then the National Guard got into their truck and left."

Another National Guard highway patrol car pulled up within minutes and called for ambulances.

A law enforcement crime-scene report on the incident largely corroborates the account of the shooting contained in the complaint. It said investigators found 83 shell casings at the scene where the shot-up SUV came to rest after crashing into a highway barrier.

Investigators interviewed the wounded 24-year-old woman, Veronica Treviño, at a hospital later, and she told them that "they started to shoot at us without any apparent reason." The occupants described the standard white National Guard pickup trucks the force uses and the light grey camouflage uniforms they wear.

Another occupant of the vehicle told investigators that the National Guard may have been pursuing a fleeing truck full of gunmen who were firing at the patrol vehicle. That witness said that, as the Guard vehicle passed the civilians' SUV in pursuit of the fleeing truck, the SUV may have inadvertently bumped into the patrol, perhaps leading Guard officer to think it was part of the attack.

Local officials in the state of Tamaulipas have apparently referred the case to federal prosecutors, since it involves federal forces.

López Obrador created the National Guard as his main law-enforcement force and has tried to put it directly under the control of the Defense Department. The vast majority of National Guard officers are on loan from the Army, and all recruits are trained by the Army.

That approach has been criticized by human rights groups, who describe it as the militarization of civilian policing. They say the armed forces aren't trained to do police work, and are prone to excessive use of force.

The shootings echo the Feb. 26 killings by soldiers, which caused outrage because the occupants of the pickup truck the army fired on were apparently not armed.

The governmental National Human Rights Commission said in a report on the Feb. 26 incident that soldiers in four patrol vehicles had followed the pickup in the pre-dawn hours based on just a "suspicion," and did not follow proper procedure in engaging the vehicle.

In Nuevo Laredo, army and guard patrols are frequently on edge because of the massive number of hitmen working for the Northeast cartel.

The city has also been the scene of human rights violations by the military in the past.

In 2021, Mexico's navy turned 30 marines over to civilian prosecutors to face justice in the cases of people who disappeared during anti-crime operations in Nuevo Laredo in 2014. Marines were accused of rounding up supposed suspects, some of whom were not heard from again. Through 2018, dozens of people disappeared in Nuevo Laredo.