WASHINGTON — A new intelligence report delivered to Congress on Wednesday by the Biden administration warned about the rising threat of militias and white supremacists, adding urgency to calls for more resources to fight the growing problem of homegrown extremism in the United States.
In particular, the intelligence assessment highlighted the threat from militias, predicting that it would be elevated in the coming months because of “contentious sociopolitical factors,” likely a reference to the fallout from the Jan. 6 riot at the Capitol by a pro-Trump mob and the increasingly partisan political climate.
Racially motivated violent extremists, such as white supremacists, were most likely to conduct mass casualty attacks against civilians while militias typically targeted law enforcement and government personnel and facilities, the report said. Lone offenders or small cells of extremists were more likely than organizations to carry out attacks, it said.
President Biden requested the comprehensive threat assessment shortly after he took office in the wake of the Jan. 6 assault on the Capitol, which laid bare the toxic domestic extremism that has shaken the country. Only the brief executive summary was declassified and made public while a classified version was sent to Congress and the White House.
The top-line assessment echoed earlier analyses by the F.B.I. and Department of Homeland Security warning of the looming dangers of domestic terrorism, including after followers of President Donald J. Trump embraced his baseless claims of election fraud. An internal F.B.I. report that appeared to have been compiled before Jan. 6 and was published days after the breach predicted the violence to come, saying the events in 2020 were “likely to embolden U.S. domestic violent extremists in 2021.”
The Homeland Security Department also previously issued a rare terrorism bulletin warning that extremists continue to be galvanized over “the presidential transition, as well as other perceived grievances fueled by false narratives,” a clear reference to Mr. Trump’s false accusations that the election was stolen.
Domestic extremism “poses the most lethal and persistent terrorism-related threat to the homeland today,” Alejandro N. Mayorkas, the homeland security secretary, told a House committee on Wednesday.
“The Jan. 6 attack on the U.S. Capitol and on American democracy is a searing example of this threat,” Mr. Mayorkas said.
The F.B.I. said in statement that the “threat is persistent and evolving.”
The F.B.I. and Department of Homeland Security have warned that the Jan. 6 riot could have lasting consequences. Some domestic violent extremists “have been emboldened in the aftermath of the breach of the U.S. Capitol,” Jill Sanborn, the head of counterterrorism at the F.B.I., told Congress this month.
The Biden administration has made fighting domestic terrorism a priority. Along with the threat assessment, the administration is also reviewing what law enforcement and intelligence agencies can do to combat domestic terrorism. The report came out the day after a deadly rampage at three spas in the Atlanta area, killing eight people, including six women of Asian descent. The shooter’s motivations were not immediately clear, but crimes against Asian-Americans and Pacific Islanders have been on the rise.
“Whatever the motivation here,” Mr. Biden told reporters on Wednesday, “I know Asian-Americans are very concerned. Because as you know I have been speaking about the brutality against Asian-Americans for the last couple months, and I think it’s very, very troubling.”
The Trump administration had added combating domestic terrorism to its National Strategy for Counterterrorism, but Mr. Trump was repeatedly reluctant to denounce the violent extremism carried out by far-right nationalists and white supremacists, sometimes embracing them and focusing his criticism instead on anarchists and other left-wing agitators.
Critics of Mr. Trump accused him of exploiting racial and socioeconomic divisions for political gain and fueling dangerous conspiracy theories that helped incite the events of Jan. 6, where hundreds of his supporters stormed the Capitol. The F.B.I. has charged more than 300 people in connection with the riots, including members of the Oath Keepers and the Proud Boys, far-right groups that backed Mr. Trump. Others charged include white supremacists.
The rise of domestic terrorism has gradually increased in recent years as the F.B.I. made fighting white supremacists a top priority in 2019 after a slew of deadly shootings in Texas, California and Pennsylvania. Last year, the F.B.I. raised the threat poised by antigovernment extremists such as militias and anarchists.
The F.B.I. director, Christopher A. Wray, has been blunt about the dangers of domestic terrorism, telling Congress this month that the events of Jan. 6 were appalling.
“That siege was criminal behavior, plain and simple, and it’s behavior that we, the F.B.I., view as domestic terrorism,” Mr. Wray said during a hearing before the Senate Judiciary Committee, adding, “The problem of domestic terrorism has been metastasizing across the country for a long time now and it’s not going away anytime soon.”
During the hearing, Mr. Wray revealed that the number of domestic terrorism cases had grown to 2,000, a significant increase since he became director in 2017. Arrests of white supremacists had also surged.
As part of F.B.I. efforts to crack down on violent white supremacists, agents have arrested members of neo-Nazi groups, including one known as the Base. The leader of the group, an American citizen who once worked in the intelligence community, moved to St. Petersburg, Russia, where the authorities believe he is recruiting new members and spreading his hateful ideology. The leader, Rinaldo Nazzaro, denies that he is working with the Russian government to sow discord in the United States as the Kremlin had done during the 2016 and 2020 elections.
The report noted that white supremacists had “the most persistent and concerning transnational connections because individuals with similar ideological beliefs exist outside of the United States.” In addition, it said that a small number of white supremacists had “traveled abroad to network with like-minded individuals.”
It also added that “several factors could increase the likelihood or lethality” of domestic terrorist attacks in 2021 and beyond, including “escalating support from persons in the United States or abroad.”
At the Senate hearing this month, Mr. Wray said he welcomed more resources such as agents and analysts to fight a variety threats facing the country — not just domestic terrorism. It is not clear if the F.B.I. will receive the funding for more personnel but the issue could receive bipartisan support. At least one prominent Republican lawmaker, Senator Lindsey Graham, seemed to embrace the idea.
“So, here’s my challenge to you, sit down and put pen to paper and in the think big, not small — what do you need that you don’t have in terms of agents and resources and put it to paper,” Mr. Graham told Mr. Wray.
Julian E. Barnes, Zolan Kanno-Youngs and Michael Schwirtz contributed reporting.
