The Secretary of Homeland Security said Monday night that an internal review focused on domestic violent extremism threats within the department is being launched.

In a memo first reported on by CBS News, DHS secretary Alejandro N. Mayorkas pointed to “recent events,” including the fatal Capitol riot in January, as having highlighted what he described as “the most lethal and persistent” terrorism threat to the U.S.

“Violent extremism has no place at DHS and we will work with urgency and focus to address it,” Mayorkas said in the memo, available in full here via the DHS. “Given the evolving threat landscape and the grave risks posed by domestic violent extremism, including to our employees and operations, I have directed the Department to immediately begin a review of how to best prevent, detect, and respond to domestic violent extremism threats within DHS. The team managing this internal effort, led by our Chief Security Officer, will report back to me with its recommendations.”

Soon, Mayorkas added, DHS officials will provide guidance to employees on the policies and procedures detailing the appropriate method of reporting insider threats “and other actions” connected with domestic violent extremism. The department will also be sending out reminders regarding policies on discriminatory and harassing behavior.

“We will not allow hateful acts or violent extremism to penetrate the fabric of our Department and fundamentally compromise our ability to protect the Homeland,” Mayorkas said.

Back in March, the DHS—alongside the Office of the Director of National Intelligence and the department of Justice—released an unclassified summary of a joint comprehensive threat assessment on domestic violent extremism. The report—available here—concluded that domestic violent extremists, better described as domestic terrorists, pose an “elevated threat” to the U.S. this year.