ALVARADO, Texas (AP) — Ten people have been arrested on attempted murder charges in connection with a shooting outside of a Texas immigration detention center that wounded a police officer, where people in black military-style clothing fired at authorities in a “planned ambush,” a U.S. attorney said.

A U.S. attorney called the wounding of a police officer an ‘ambush’ and warned of increasing violence against immigration agents.

One police officer was wounded after at least two people shot at officers outside an immigration detention center in Texas, according to a criminal complaint in federal court.