President Donald Trump said he would seek to designate antifa as a “major terrorist organization,” saying that the far-left-wing group was “sick” and “dangerous.”

The president in a social media post said he would also “strongly recommend” that whoever funds the actions of antifa groups should be investigated.

“I am pleased to inform our many U.S.A. Patriots that I am designating ANTIFA, A SICK, DANGEROUS, RADICAL LEFT DISASTER, AS A MAJOR TERRORIST ORGANIZATION,” Trump said.

He added, “I will also be strongly recommending that those funding ANTIFA be thoroughly investigated in accordance with the highest legal standards and practices. Thank you for your attention to this matter!”

It was not immediately clear how such a designation would be made for antifa, which is an umbrella description for far-left-leaning militant groups opposing fascists and neo-Nazis. Antifa does not have a publicly known centralized structure or leadership. The U.S. does not maintain a public list of domestic terrorist groups, although the State Department does maintain a list of Designated Foreign Terrorist Organizations.

Nor was it immediately clear how federal law enforcement authorities might make use of such a designation.

The Congressional Research Service, which collects and analyzes policy details for Congress, said in a 2023 report that while federal law enforcement plays a “significant role” in combating domestic terrorism, there exists a grey area between combating potential violence associated with domestic terrorism and publicly identifying those with extreme beliefs.

Holding extreme beliefs is not, in itself, criminal in the United States, since those beliefs are protected under the First Amendment, the report said.

“Further, the U.S. government does not provide a precise, comprehensive, and public explanation of any particular groups it might consider to be domestic terrorist organizations,” that report said. “Listing groups in this way may infringe on First Amendment-protected free speech—or the act of belonging to an ideological group, which in and of itself is not a crime in the United States.”

Trump’s comments on social media on Wednesday followed others he and members of his administration have made about antifa and left-leaning groups in the wake of the fatal shooting of political activist Charlie Kirk.

Trump on Monday said during an Oval Office event that he thinks Tyler Robinson, 22, the suspect charged in Kirk’s killing, may have been “radicalized” toward the “left” in a short period of time through his use of the internet.

“That’s my opinion, I think he was radicalized online based on what they’re saying,” Trump said.

“That’s just by watching the same things that you’re watching and hearing it looks like he became radicalized over the internet,” Trump said, then suggesting that his parents, who are allegedly Republican-aligned, were “wonderful.”

“Looks like he was radicalized over the internet, and it’s radicalized on the left, he’s a left. A lot of problems with the left, and they get protected, and they shouldn’t be protected,” Trump added.

He later added on Monday that he would “100%” consider designating antifa as a domestic terror organization.

It was not clear whether Robinson was influenced by or affiliated with antifa.

Deputy Chief of Staff Steven Miller on Monday said the White House would be targeting nongovernmental organizations that they said were fomenting violence.

“What you’re referring to is there are these nonprofit entities that organize, as the president mentioned, attacks on ICE officers, attacks on Border Patrol agents, organized doxing campaigns, which are a violation of federal law,” Miller said.

He added, “So there’s this whole network of organizations. And I think the key point the president’s been making is somebody is paying for all of this. This is not happening for free. And so under the president’s direction, the attorney general is going to find out who is paying for it, and they will not be criminally liable for paying for violence.”