WASHINGTON — President-elect Joseph R. Biden’s nominee to be the next director of national intelligence said on Tuesday that the incoming administration would step up efforts to examine foreign interference in American politics, including overseas efforts to influence domestic extremists groups like those tied to the QAnon conspiracy theory movement.
Avril D. Haines, Mr. Biden’s nominee, told the Senate Intelligence Committee that she would work to establish a center within the intelligence community on foreign malign influences and assist the F.B.I. and Department of Homeland Security with a public written assessment of the threat from QAnon.
Even before a pro-Trump mob struck the Capitol on Jan. 6, the Biden transition team had been discussing how intelligence agencies could increase scrutiny on efforts by foreign powers to influence extremist groups in America.
But in the aftermath of the riot, and reports that Russia and other countries have been trying to amplify disinformation about it, the Biden team has put even greater emphasis on how to counter domestic extremist groups.
The pro-Trump mob included some followers of QAnon, a wide-ranging online movement that falsely claims that President Trump is on a crusade to rid the world of satanic pedophiles organized by the Democratic Party and Hollywood celebrities.
Intelligence officials have tracked the spread of QAnon theories to Germany, Japan and other countries. And people who have spoken to the Biden transition team say the incoming administration wants to build on that work to see if foreign governments have in turn tried to promote the spread of QAnon, or other extremist right-wing movements, in America.
Several Democratic senators asked Ms. Haines on Tuesday about the threat of right-wing extremist groups. In her responses, Ms. Haines had to walk a fine line, since restrictions limit the information intelligence agencies can collect about Americans and American groups.
She said she would make sure the agencies examined “connections between folks in the U.S. and externally,” but made clear that the F.B.I. and Department of Homeland Security would have to take the lead on such investigations.
Ms. Haines, an expert in international law, has worked for the Obama and George W. Bush administrations in jobs for the National Security Council, the State Department and the C.I.A.
At Tuesday’s hearing, Dan Coats, a former director of national intelligence, outlined some of Ms. Haines’s colorful background. Before going to law school and joining the federal government, Ms. Haines had a career featuring airplane restoration, running an independent bookstore and studying physics, prompting her description as “the least likely spy” in a 2013 profile by the veteran national security reporter Daniel Klaidman.
If confirmed, Ms. Haines will lead the Office of the Director of National Intelligence and help oversee the nation’s intelligence agencies, which now number 18 with the addition of the intelligence arm of the Space Force this month.
She will be assigned to rebuild an intelligence community that was openly excoriated by Mr. Trump over its assessment that Russia had interfered on his behalf in the 2016 election and to depoliticize the Office of the Director of National Intelligence.
Senator Martin Heinrich, Democrat of New Mexico, pressed Ms. Haines on what the intelligence agencies could do about “domestic radicalized groups in the United States.” He noted that the State Department had a process for designating foreign groups as terrorist organizations.
“We don’t have any sort of process for domestic terrorist organizations,” he said.
Mr. Heinrich pointed to a letter he and other Senate Democrats wrote to the F.B.I. and Homeland Security Department about QAnon’s “spread of disinformation.” He asked Ms. Haines if she would commit to helping with that assessment. She said she would look for answers on how “foreign influence operations” were affecting QAnon.
“The intelligence community is focused on foreign intelligence and on foreign threats,” she said. “But there is a critical role that it can play and does play in supporting the work that’s done by others.”
Senator Mark Warner, a Virginia Democrat who is set to become the chairman of the Senate Intelligence Committee, noted that the rise of extremist groups was not a phenomenon confined to America.
“We’ve seen similar right-wing groups springing up across many European nations and some level of networking between what’s happening in Europe and what’s happening in this country,” Mr. Warner said.
Since the Jan. 6 siege, intelligence officials have seen Chinese, Iranian and Russian efforts to fan violent messaging, according to a joint threat assessment by federal law enforcement officials drafted last week.
On Friday, the Democratic and Republican leaders of the Senate Intelligence Committee jointly asked the current director of national intelligence, John Ratcliffe, for information about any “efforts by foreign actors to disrupt the inauguration” as well as information on how the nation’s spy agencies were aiding law enforcement to warn of further unrest.
Intelligence agencies have tracked foreign powers seeking to amplify discussion and misinformation about the riot. That includes Russian efforts to push the false line that members of antifa were to blame for the attack, not right-wing extremists.