Mayorkas, 61, will also stand at the center of Biden's attempts to reverse many immigration restrictions put in place by Republican former President Donald Trump.
The DHS advisory said domestic violent extremists were motivated by issues including anger over COVID-19 restrictions, the 2020 election results, and police use of force.
In testimony before the U.S. House of Representatives Intelligence Committee, former intelligence chief Brian Murphy accused department leadership of urging him to "blame Far Left groups in an exaggerated fashion.
"The cheap cotton goods you may be buying for family and friends during this season of giving - if coming from China - may have been made by slave labor ...
The shift in attention comes after years of election-related anxiety revolving around the integrity of vote tallying machines and electronic poll books.
Schiff said he also had issued a subpoena to force DHS to turn over "documents, communications, and other records" related to the committee's probe of Murphy's allegations.