A detainee has died and two others are critically injured after a rooftop sniper opened fire at an Immigration and Customs Enforcement (ICE) centre in Dallas, Texas, officials say.

The gunman fired indiscriminately at the ICE facility and at a nearby unmarked van, law enforcement officials say, before dying from a self-inflicted gunshot wound.

No law enforcement were injured. FBI Director Kash Patel posted a photo on X of unused ammunition recovered from the scene. One casing has the phrase “ANTI-ICE” on it.

It is the latest in a string of attacks on ICE facilities in recent months as the agency ramps up efforts to deliver on US President Donald Trump’s pledge for mass deportations.

“While the investigation is ongoing, an initial review of the evidence shows an ideological motive behind this attack,” Patel wrote on X.

“These despicable, politically motivated attacks against law enforcement are not a one-off.”

Dallas police said officers responded to an assist officer call at the facility around 06:40 local time (11:40  GMT).

The Department of Homeland Security (DHS) said three detainees were shot. One has died, and two were critically injured, it said. They remain in critical condition, officials later said.

The department had initially said two people had died in addition to the shooter, only to revise that information conditions hours later.

One injured detainee is a Mexican national, the Mexican foreign ministry said.

Acting ICE director Todd Lyons identified the shooter as 29-year-old Joshua Jahn, the BBC’s US partner, CBS News reported. He died of a self-inflicted gunshot wound, authorities said.

Voter records indicate he was registered as an independent and last voted in the general election in 2024.

Jahn had cannabis related charges in Texas dating back to 2016, according to records seen by the BBC.

FBI special agent Joe Rothrock told a news conference that rounds found near the gunman contained “messages that are anti-ICE in nature”.

“This is just the most recent example of this type of attack,” he said, adding the FBI was investigating it as “an act of targeted violence”.

Dallas police said a preliminary investigation determined the suspect had opened fire from an adjacent building.

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

The Reuters news agency reported that the building targeted is an ICE field office used for short-term processing of recently arrested detainees, and is not used as a detention facility.

Lyons told CBS News on Wednesday that the shooter deliberately targeted law enforcement with a “high-powered rifle”.

He said given the time are area of the shooting, it could have been more deadly.

The suspect “could have, in his indiscriminate fire, hit people traveling to work, civilians on the ground,” he said.

Edwin Cardona, a Dallas resident from Venezuela, told local media he was entering the building for an appointment when he heard gunfire.

“I was afraid for my family because my family was outside. I felt terrible because I thought something could happen to them. Thank God no,” he said.

Acting director of the Dallas ICE office Joshua Johnson told the news conference it was the second time he has had to stand in front of the media and talk about a gunman at one of his facilities.

“The takeaway from all of this is that the rhetoric has to stop,” he said.

Texas Senator Ted Cruz also spoke at the news conference, condemning “politically motivated violence”.

“Your political opponents are not Nazis,” he said, urging people not to demonise each other for partisan reasons. “The divisive rhetoric, tragically, has real consequences.”

While the shooter’s motive remains unclear, the attack comes amid growing concerns in the US about political violence in the wake of the killing of conservative activist Charlie Kirk this month.

US President Donald Trump, in a lengthy post on social media on Wednesday evening, said ICE officers are facing “an unprecedented increase in threats” and accused “Radical Left Democrats” of “constantly demonizing Law Enforcement”.

Trump noted on Monday he signed an executive order designating Antifa a terrorist organisation, and added he would sign another this week to “dismantle these Domestic Terrorism Networks”.

No information has been released by officials to suggest Antifa – a loosely organised, leftist movement that opposes far-right, racist and fascist groups – has any connection to the shooting.

Homeland Security Secretary Kristi Noem said in a statement: “This shooting must serve as a wake-up call to the far-left that their rhetoric about ICE has consequences.”

Democratic lawmakers also condemned the shooting, including Senator Cory Booker who called it “an unacceptable act of violence”.

“While we don’t know all of the details yet, what we can, and all should, agree on is that the vilification of any group of people endangers them. It makes them targets. And it must stop,” he said on X.

Republican Governor of Texas Greg Abbott said on X the shooting would “NOT slow our arrest, detention, & deportation of illegal immigrants”.

The ICE field office in Dallas has been targeted by a series of protests this summer.

A man was arrested in August after he entered the facility claiming to have a bomb in his backpack, according to the DHS.

The 36-year-old US citizen, Bratton Dean Wilkinson, had shown the building’s security staff a device on his wrist that he described as a bomb “detonator,” the DHS said.

Last month shots were fired at ICE offices in San Antonio, Texas. No injuries were reported in that incident, which ICE blamed on “political rhetoric”.

Another shooting occurred on the 4 July public holiday at an ICE facility in Alvarado, Texas, after a protest escalated into a face-off with police. An officer was shot in the neck, and survived. Eleven people have been charged over that attack.