(NewsNation) — The FBI is investigating a deadly shooting at a U.S. Immigration and Customs Enforcement field office in Dallas as an act of targeted violence, officials said Wednesday.

One detainee at the facility was killed and pronounced dead at the scene, a Homeland Security spokesperson said. Two other detainees were critically injured. DHS said that the victims were shot in a transport van which was in the facility’s sallyport where the van was located.

NewsNation’s Ali Bradley confirmed through sources that the suspected shooter is 29-year-old Joshua Jahn from Collin County, Texas, north of Dallas, who reportedly died by suicide.

Mexico’s Ministry of Foreign Affairs confirmed that one of the people who was critically injured is a Mexican national. Authorities declined to identify the victims in Wednesday’s shooting.

Police believe the shooter opened fire from a nearby building at approximately 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, Rothrock confirmed. The suspect died by suicide, according to Homeland Security Secretary Kristi Noem.

DHS officials said in a statement that a sniper fired “indiscriminately” at the ICE field office from a nearby rooftop.

Dallas Mayor Eric Johnson asked everyone to pray for the families of those who lost their lives and the speedy recovery of those injured.

He also asked residents of Dallas to remain calm, stay patient and let law enforcement do their jobs in investigating: “Exercise a little bit of restraint.”

NewsNation crews observed SWAT trucks responding early Wednesday morning. The Dallas Bureau of Alcohol, Tobacco, Firearms and Explosives and FBI agents are assisting, the agencies confirmed.

Assistant DHS Secretary Tricia McLaughlin said the shooting came as ICE personnel face a “1000% increase” in assaults. The department has not provided hard data to back that number.

Trump blames shooting on ‘Radical left’ Democrats for demonizing ICE

President Donald Trump called the shooter allegedly writing “Anti-ICE” on one of the bullet casings “despicable” and blamed “Radical left Democrats” who demonize law enforcement.

In a Truth Social post, Trump wrote that the “brave men and women of ICE” are removing the “worst of the worst” criminals but are “facing an unprecedented increase in threats, violence and attacks” by the deranged radical leftists,” the president wrote on Truth Social.

“This violence is the result of the Radical Left Democrats constantly demonizing Law Enforcement, calling for ICE to be demolished, and comparing ICE Officers to “Nazis.” The continuing violence from Radical Left Terrorists, in the aftermath of Charlie Kirk’s assassination, must be stopped.”

Vance ‘pretty confident’ shooting was ‘left-wing, political attack’

Vice President JD Vance also blamed the left-wing for Wednesday’s shooting, telling Nextstar Washington Correspondent Reshad Hudson that political leanings played a key role.

“We do feel pretty confident,” Vance told Nexstar in the interview. “This was a motivated, left-wing, political attack. And that I think goes to show that we just have way too much of this in our country, especially in the last couple of weeks. And I think I’d encourage everybody to really tone down the rhetoric when it comes, particularly to our law enforcement and our ICE agents.”

He added, “I think we all need to tone down the temperature a little bit. I think in particular, my Democratic colleagues need to ask some very hard questions about why it is that folks from their side of the political aisle seem to be engaged in these politically motivated attacks, and I think it’s important for them to look in the mirror and say, wait a minute. Can we look at the mirror? Can we actually take some steps to police some of the violent rhetoric on our own side? Because unless they do, I fear stuff like that? This is going to keep on happening.”

Earlier on Wednesday, Vance called the shooting an “obsessive attack on law enforcement,” and Texas Gov. Gregg Abbott called it an “assassination.”

Texas Democrats ‘horrified’ by Dallas shooting, condemn violence

The Texas Democratic Delegation, which includes nine lawmakers, issued a statement saying the group is “horrified” at the shooting that took place at the Dallas ICE field office.

“We unequivocally condemn all forms of violence and urge everyone to refrain from rhetoric that fans the flames—from all sides,” the Democratic Delegation said. “No one — those in uniform, civilians, or immigrants — should be subject to the senseless violence we are seeing across our nation.

“The Trump Administration and the Governor must stop stoking the flames of division, hate, and anger to exploit people’s fears for political gain. As more details of the shooting emerge, we urge everyone to meet this moment with empathy and not give into the lies and hateful rhetoric we are already seeing.”

Threats, allegations at Dallas-area ICE facilities

A man threatened ICE officers and claimed to have a bomb at the same field office on Aug. 26, according to DHS. The suspect, a 36-year-old American citizen, was arrested and charged with making terroristic threats.

In recent months, federal lawmakers and activists have alleged “inhumane” treatment of detainees at the field office, including the withholding of food, water, air conditioning or proper sleeping quarters.

About 40 miles southwest of Dallas at the Prairieland Detention Center in Alvarado, a July 4 “planned ambush” wounded a police officer and led to the arrests of 10 people involved.

The attackers set off fireworks, vandalized structures with phrases like “ICE pig” and “traitor,” and attacked a responding police officer.

U.S. Sen. Ted Cruz, R-Texas, said that Wednesday’s deadly shooting was the third in Texas that has been aimed at either ICE officers or Customs and Border Protection agents.

Noem wrote in a social media post that she has been warning politicians and media for months to “tone down” anti-ICE rhetoric before someone was killed.

“These horrendous killings must serve as a wake-up call to the far-left that their rhetoric about ICE has consequences. Comparing ICE day in and day out to the Nazi Gestapo, the Secret Police, and slave patrols has consequences,” Noem wrote on X. “The men and women of ICE are fathers and mothers, sons and daughters. They get up every morning to try and make our communities safer. Like everyone else, we just want to go home to our families at night. The violence and dehumanization of these men and women who are simply enforcing the law must stop.”

NewsNation’s Ali Bradley contributed to this report.