The Department of Homeland Security last week warned of potential violence directed at migrants and other targets related to the end of Title 42, the public health rule that ensures federal officials can continue to immediately expel migrants at the U.S.-Mexico border.
"So far, we have observed calls for attacks targeting primarily migrants and critical infrastructure, but our insight ... is constrained by these individuals' use of online security measures to limit exposure to law enforcement," reads the memo, dated Dec. 23, CNN reported.
The report came a day after the Supreme Court ruled that Title 42 must remain in effect as it considers if states can challenge the Biden administration's attempt to end it.
Immigration has been the subject of heated debate for years, with Republicans and Democrats at odds over how to handle thousands of migrants arriving at the U.S. southern border. Republican leaders have implemented a new strategy, further escalating tensions, by sending immigrants to Democrat-led cities.
The DHS memo, from the department's Office of Intelligence and Analysis, cited violent tactics discussed among social media users against migrants, including "firearms attacks, the placement of land mines along migration routes, and luring migrants into trailers to poison them with gas."
Other users discussed shooting electrical substations near the border.
"We have not previously observed calls for substation attacks in response to immigration-related concerns, and these recent discussions may stem from widespread media coverage of recent attacks against other substations across the United States, particularly in Moore County, North Carolina," the memo reads.
DHS also acknowledged in the memo that domestic violent extremists have historically cited "immigration-related grievances."