Acting Immigration and Customs Enforcement Director Todd Lyons said he would put all ICE facilities on a higher alert following a shooting at a Dallas field office on Wednesday which killed one detainee and critically wounded two others.

While no officers were injured, the Department of Homeland Security said the shooting was “an attack on ICE law enforcement.”

The suspected shooter has been identified by law enforcement officials as 29-year-old Joshua Jahn, multiple law enforcement sources told ABC News.

The shooter, who was on a nearby rooftop, “fired indiscriminately at the ICE building, including at a van in the sallyport where the victims were shot,” DHS said in a statement.

The shooter died from a self-inflicted gunshot wound, officials said.

DHS previously said two detainees were killed and one was injured; the agency later issued a correction saying one died and two were shot but survived.

One of the wounded is a Mexican national, according to Mexico’s Ministry of Foreign Affairs.

Law enforcement and Republican politicians suggested a political motive for the shooting, which comes amid ramped up ICE deportation efforts throughout the country. The DHS said in a statement that ICE officers have faced a more than 1,000% increase in assaults against them.

Two Texas facilities were targeted this July: a police officer was shot at an ICE detention facility in Alvarado and a gunman opened fire at the entrance of the Border Patrol sector annex in McAllen.

The FBI said Wednesday’s shooting is being investigated “as an act of targeted violence.”

FBI special agent Joe Rothrock said it appeared that rounds “found near the suspected shooter contain messages that are anti-ICE in nature.”

FBI Director Kash Patel released an image of recovered bullets, including one engraved with the phrase “ANTI-ICE,” and DHS released a photo that appears to show a gunshot in an American flag display.

Vice President JD Vance said during remarks in North Carolina on Wednesday that evidence that has not yet been released shows the shooter was a “left-wing extremist” who was “politically motivated to go after people who are enforcing our border.”

Officials said that attacks on ICE and law enforcement must end.

“Our prayers are with the families of those killed and our ICE law enforcement. This vile attack was motivated by hatred for ICE,” DHS Secretary Kristi Noem said in a statement. “For months, we’ve been warning politicians and the media to tone down their rhetoric about ICE law enforcement before someone was killed. This shooting must serve as a wake-up call.”

President Donald Trump wrote on social media, “This is despicable! The Brave Men and Women of ICE are just trying to do their jobs, and remove the ‘WORST of the WORST’ Criminals out of our Country, but they are facing an unprecedented increase in threats, violence, and attacks by Deranged Radical Leftists.”

“This needs to stop,” Sen. Ted Cruz, R-Texas, said at a news conference. “Violence is wrong, politically motivated violence is wrong.”

Vance said, “We’re praying both for our ICE agents, but also for everybody who’s affected by this terrible attack.”

House Democratic leaders in a statement thanked the first responders and offered their condolences to the victims’ families.

“No one in America should be violently targeted, including our men and women in law enforcement who protect and serve our neighborhoods, and the immigrants who are too often the victims of dehumanizing rhetoric,” the Democrats’ statement continued. “The political and ideologically-motivated violence in America has reached a breaking point this year. We need leaders who bring the country together in moments of crisis.”

ABC News’ Mireya Villarreal and Jim Scholz contributed to this report.