EL PASO, Texas (Border Report) — U.S. Border Patrol agents from a tactical unit shot and killed a migrant who was armed when he entered the country illegally.

According to a U.S. Customs and Border Protection statement, a Border Patrol remote camera operator spotted six individuals entering the country illegally on Oct. 30, about 2 miles west of the San Luis Port of Entry in San Luis, Arizona. CBP said the camera operator observed that one of the migrants was armed with a handgun and relayed the message to agents with the Border Patrol Tactical Unit, or BORTAC, who responded to the area.

Agents encountered the group of migrants shortly after 7 p.m. about 300 yards from the U.S.-Mexico border. During the encounter, CBP said, three agents fired their weapons, striking and killing one of the subjects.

CBP said that man who was killed was an armed Mexican national, adding that a handgun was found near his body. Agents apprehended four of the individuals, while one ran back into Mexico.

CBP’s statement did not say what prompted the agents to open fire.

Border Report reached out to CBP and asked to clarify whether the armed man shot at agents or threatened to shoot agents.

A CBP spokesman referred Border Report to the statement: “That is the releasable information at this time.”

According to the statement, the FBI, San Luis Police Department, Department of Homeland Security’s Office of Inspector General and CBP’s OPR responded to the scene, and all are investigating the incident.