EL PASO, Texas (Border Report) ⁠— The individuals who were shot with pepper balls while swimming in the Rio Grande allegedly threw rocks at agents, a Border Patrol spokesman told Border Report.

On Sunday evening, dozens of people could be seen swimming in the Rio Grande right next to the American Dam, which is operated by the U.S. International Boundary and Water Commission. It’s a popular destination where people find respite from the desert heat, and where food vendors set up shop on the river banks and provide refreshments for families enjoying an outing on the river.

Border agents initially responded to a radio call for assistance on an ongoing assault involving an IWBC security guard. The guard reportedly upset some of the people when he told them to move away from the dam gates.

When they got to the IWBC property, agents encountered a large group of people who allegedly threw rocks and refused to leave, prompting agents to utilize Pepperball Launching Systems to disperse the group, the Border Patrol spokesman said. The PLS fires non-lethal pepper balls, which are described as a “frangible projectiles containing a powdered chemical that irritates the eyes and nose similar to pepper spray.”

The crowd booed when the first shots were fired.

Two men who were hit with pepper balls showed a reporter the welts on their bodies. They said the agent fired at least 12 shots.

Other agencies responded, including Juarez Municipal Police on the Mexican Side. All of the individuals returned to Mexico without further incident.

This use of force has drawn criticism from activists, who urged the Border Patrol to investigate and review use-of-force policies.

In a statement, the Border Network for Human Rights said, “This incident regresses on real progress that the El Paso Border Patrol Sector had made in reducing their use of force. We know that tactics to de-escalate encounters make life safer for migrants, Borderland residents, and agents.

“Border Patrol must remember that the rights, dignity, and lives of all persons are important, and this excessive use of force does nothing to meet the needs of border communities or uphold the values and ideals of America.”

The director of BNHR, Fernando Garcia, said that in the coming day his organization “will reach out to the Border Patrol Sector Chief to discuss this incident and ensure Border Patrol hears and addresses the needs and experiences of area residents.”