The Department of Homeland Security on Tuesday dedicated an arm of its intelligence division to target domestic terrorism and opened a new center to help state and local law enforcement combat violent extremists, the latest Biden administration efforts on the problem in the wake of the Jan. 6 siege on the Capitol.

The department said the moves were part of a strategy to “comprehensively combat domestic violent extremism, including violent white supremacy.”

President Biden asked federal intelligence agencies to assess the threat of domestic terrorism shortly after he took office. In March, the administration released a report that warned about the increasing threat from militias and white supremacists, which amplified calls for the need to fight extremism inside the United States.

“Individuals who may be radicalizing, or have radicalized, to violence typically exhibit behaviors that are recognizable to many but are best understood by those closest to them, such as friends, family, and classmates,” the homeland security secretary, Alejandro N. Mayorkas, said in a statement Tuesday afternoon.

In the aftermath of the deadly Jan. 6 riot by a pro-Trump mob, federal law enforcement was widely criticized for not responding to a threat that was evolving publicly on social media.

On Wednesday, Mr. Mayorkas is set to testify alongside Attorney General Merrick B. Garland before the Senate Appropriations Committee about the current threat posed by domestic extremists.

Mr. Mayorkas emphasized that the department’s new programs were developed to comply with privacy protections required by law. The new center will replace a similar program that was started during the Trump administration.