On Wednesday morning, three individuals in custody were shot at the Dallas Immigration and Customs Enforcement (ICE) field office during a transfer in the facility’s sally port, according to law enforcement sources reported by ABC News.

“Multiple” victims are dead, acting ICE Director Todd Lyons told ABC News, while Dallas police said one person was killed and two were hurt.

The perpetrator, described by Lyons as “a sniper from an elevated position,” fired from “a few hundred yards” away and succumbed to a self-inflicted gunshot wound. Dallas police indicated that the shots were likely fired from a nearby building.

Officers exchanged fire with the shooter, according to Lyons said, who added that “all ICE agents and officers at [the] location are accounted for.”

This marks the second attack on an ICE facility in Texas, with the first being the incident at the Prarieland Detention Center in Alvarado, Texas, last July. Lyons mentioned that he would increase security measures at all ICE locations to ensure the safety of agents and civilians engaged in the agency’s work.

This is a developing story. Please check back for updates.