(CNN) The Department of Homeland Security has uncovered "significant gaps" in its ability to detect potential domestic violent extremist threats within its ranks, citing unresolved issues of funding, training and consistency, according to a report released Friday.
DHS officials have repeatedly pointed to domestic violent extremism as one of the most lethal and persistent terrorism-related threats to the United States.
But the report found that DHS did not adequately track domestic violent extremism allegations and investigations among its own employees.
The internal review, launched last year, identified four incidents involving people in the department supporting or participating in violent extremist activity. The number, however, may be higher, the report concluded.
The four employee incidents were not identified in the report, but one involved a Coast Guard lieutenant accused of plotting a domestic terror attack, who pleaded guilty in 2019 to four counts of weapons and drug charges.
Last April, in the wake of the January 6 riot at the US Capitol, Homeland Security Secretary Alejandro Mayorkas called for the internal review, forming a working group to examine how to best "prevent, detect, and respond" to domestic violent extremism threats within DHS.
Several issues with data collection may have led to underreporting of the extremist activity, the review found. The report looked at data between fiscal year 2019 and the third quarter of fiscal year 2021, which ended in June 2021.
"To ensure we are able to continue executing our critical mission with honor and integrity, we will not tolerate hateful acts or violent extremist activity within our Department," Mayorkas said in a statement, adding that DHS will act "with urgency to better prevent, detect, and respond to potential internal threats related to domestic violent extremism, and protect the integrity of our mission."
DHS, which has more than 250,000 employees, is responsible for protecting the country from a range of threats. It has a sprawling mission that includes agencies like the Transportation Security Administration and US Customs and Border Protection.
One of the issues uncovered was the lack of an official definition of "domestic violent extremist," according to the report, as well as a lack of workforce training and insufficient funding to expand the department's insider threat program.
The working group issued 15 recommendations in its report, including adopting a consistent definition and descriptions of violent extremist activity. Mayorkas has directed DHS to "swiftly implement the report's recommendations," the department said.
DHS needs "to have an enforceable standard of what conduct will get you disciplined," Thomas Warrick, senior fellow and director of The Future of DHS Project at the Atlantic Council, told CNN. "And that is going to have to be developed."
Recommendations also include educating and training the DHS workforce and promoting early intervention to get support to employees who may be at risk of being radicalized to violence.