Initial backlash to Biden's policy shift also signals it could be challenged in court, from both those who favor restricting immigration and advocates for asylum-seekers.
The order enables U.S. officials to rapidly expel migrants at both the southern and northern borders during the COVID-19 pandemic, essentially cutting off access to asylum for most migrants.
Officials warn that online chatter could include early warning signals of planned attacks around the inauguration of Joe Biden in Washington on Wednesday.
Law enforcement, which has warned of potential violence around the Nov. 3 vote, must prepare for a range of potential threats, officials say.
