() Officials with the Department of Homeland Security say the agency will immediately increase security at Immigration and Customs Enforcement facilities across the U.S. following Wednesday’s shooting at an ICE field office in Dallas.

A gunman killed one migrant detainee and seriously wounded two others during what DHS Assistant Secretary Tricia McLaughlin called an attack “motivated by hatred for ICE.”

McLaughlin said the Texas incident is the latest in a string of “unprecedented acts of violence against ICE law enforcement,” which has included bomb threats, assaults and the online doxing of officers and their families.

“Our ICE officers are facing a more than 1,000% increase in assaults against them,” McLaughlin said in a prepared statement. “For months, we’ve been warning politicians and the media to tone down their rhetoric about ICE law enforcement before someone was killed.”

The Trump administration’s use of ICE officers to enforce immigration laws and deport undocumented individuals has generated controversy, with critics saying that otherwise law-abiding migrants have been swept up in raids. The White House says its main priority has been to clear the U.S. of migrants who commit serious or violent offenses, which it has called “the worst of the worst.”

In June, President Donald Trump federalized the National Guard and sent troops to Los Angeles when protests over ICE workplace raids turned violent in the largely Hispanic city. The Republican president has criticized so-called sanctuary cities including L.A. and Chicago for refusing to work with federal immigration authorities.

In the Dallas attack Wednesday, police believe the shooter opened fire from a nearby building around 6:40 a.m. Rounds found near the suspected shooter had messages that were “anti-ICE in nature,” said Joseph Rothrock, FBI special agent in charge of the Dallas Field Office.

No law enforcement personnel were injured. The suspect died by suicide, officials said.