A shooter killed at least one person and wounded others in a shooting on Wednesday at an Immigration and Customs Enforcement (ICE) field office in Dallas before dying of a self-inflicted gunshot wound, local and federal authorities said.

Police responded to reports of the shooting at the office in northwest Dallas at about 6.40am local time, the Dallas Police Department said on social media.

The suspect opened fire on the office from an adjacent building, according to the preliminary investigation, police said. Two people were transported to a hospital with gunshot wounds, while a third person died at the scene.

Homeland Security Secretary Kristi Noem said the shooter died from a self-inflicted gunshot wound.

“While we don’t know motive yet, we know that our ICE law enforcement is facing unprecedented violence against them,” Noem said on social media. “It must stop.”

“The obsessive attack on law enforcement, particularly ICE, must stop. I’m praying for everyone hurt in this attack and for their families,” US Vice-President J.D. Vance wrote on social media, replying to Noem.