FBI Stays on High Alert as DHS Memo Warns of Lone‑Actor, Cyber Threats During Iran War
Federal authorities have placed counterterrorism resources on high alert after a DHS memo warned of potential lone‑actor violence and lower‑level cyberattacks tied to U.S.–Israeli strikes on Iran, with FBI Director Kash Patel ordering Joint Terrorism Task Forces nationwide to mobilize assisting assets. Local police and U.S. Northern Command have heightened security at transit hubs, places of worship, the U.S. Capitol and military installation gates, while the FBI is probing the March 2 Austin mass shooting amid reports of Iranian flags and imagery and experts warn of possible sleeper cells and lone sympathizers—though no specific, credible domestic plots have been publicly identified.
📌 Key Facts
- A weekend DHS memo warned of potential lower-level cyberattacks and lone-actor violence tied to U.S.–Israeli bombing of Iran, though it did not name any specific plots.
- The FBI has been placed on high alert: Director Kash Patel ordered federal counterterrorism and intelligence units to "mobilize all assisting security assets needed," and Joint Terrorism Task Forces nationwide are ready to support local law enforcement.
- Federal, state and local authorities have increased visible security: U.S. Northern Command directed heightened checks at all military installations (including Camp Lejeune); Metropolitan Police (D.C.), Metro Transit Police, NYPD and LAPD boosted patrols at transit hubs, places of worship and other sensitive sites; and the House Sergeant-at-Arms notified offices of heightened security across the Capitol campus and coordination with partners.
- Reporting emphasizes that no specific, publicly disclosed, credible domestic plots have been identified even as agencies mobilize resources.
- The FBI and other agencies are investigating the March 2 Austin mass shooting in the context of the Iran-related tensions: alleged shooter Ndiaga Diagne is accused of killing three and wounding 14, and investigators say an Iranian-flag design and regime‑leader photos were found in his home; motive remains under investigation.
- The Pentagon is moving more U.S. tactical aviation assets into the Middle East; Joint Chiefs Chairman Gen. Dan Caine said the mission is to degrade Iran’s ability to project power and pursue a nuclear weapon.
- Former FBI assistant director Chris Swecker warned that Hezbollah and Hamas have maintained a presence in the U.S. since the 1980s, said "if they were going to act violently, it's now," and warned of "lone sympathizers" in domestic protest movements—while tying increased risk to what he described as "four years of open borders," without citing specific cases.
- Retired FBI supervisory special agent Jason Pack noted that heightened monitoring around conflicts is standard and that U.S. military action alongside Israel can significantly shift the domestic threat environment.
📰 Source Timeline (6)
Follow how coverage of this story developed over time
March 02, 2026
7:24 PM
U.S. Capitol security "heightened" due to Iran conflict
New information:
- House Sergeant-at-Arms William McFarland emailed House offices Monday saying there will be 'heightened security measures and a noticeable increased police presence across the U.S. Capitol campus.'
- McFarland said the Office of the Sergeant at Arms is working closely with other law enforcement and intelligence partners to monitor 'the ongoing conflicts in the Middle East.'
- The email frames the Capitol precautions explicitly as a response to the escalating conflict involving Iran.
6:38 PM
FBI remains on high alert, DHS memo warns of lone wolf attacks amid war with Iran
New information:
- Confirms a weekend DHS memo warning specifically of potential lower‑level cyberattacks and lone‑wolf violence tied to U.S.–Israeli bombing of Iran, though without naming particular plots.
- Quotes a senior FBI official saying the Joint Terrorism Task Forces nationwide remain on high alert with all resources ready to support local law enforcement.
- Explicitly links the March 2 Austin mass shooting — in which naturalized U.S. citizen Ndiaga Diagne allegedly killed three and wounded 14 — to early investigative findings that an Iranian flag and regime‑leader photos were found in his home, placing the case squarely in the Iran‑war threat context.
- Adds fresh Pentagon detail from Joint Chiefs Chairman Gen. Dan Caine that more U.S. tactical aviation assets are flowing into the Middle East, and reiterates the stated mission of degrading Iran’s ability to project power and build a nuclear weapon.
12:03 AM
U.S. cities step up security measures amid Iran tensions
New information:
- FBI Director Kash Patel publicly instructed federal counterterrorism and intelligence units to 'mobilize all assisting security assets needed' and placed them on high alert, per a post on X.
- U.S. Northern Command directed all U.S. military installations, including Camp Lejeune, to implement heightened security measures at all entry gates 'until further notice' due to ongoing operations in the Middle East.
- Metropolitan Police in Washington, D.C., Metro Transit Police, NYPD and LAPD all announced increased patrols or visible presence at sensitive locations, including transit hubs and places of worship, following the Iran strikes.
- U.S. Capitol Police stated they have been operating in a heightened threat environment 'for a long time' and are working with partners under an elevated security posture, though they declined to give specifics.
- The article notes that the intensified security announcements are unfolding as the FBI investigates an Austin, Texas mass shooting where the alleged gunman reportedly wore a shirt with an Iranian flag design, though motive remains under investigation.
March 01, 2026
5:33 PM
Enemy within: Counterterrorism experts fear sleeper cells could be poised inside USto
New information:
- Former FBI Assistant Director Chris Swecker tells Fox News that if Hezbollah or Hamas cells are going to act violently in the U.S., 'it's now,' and asserts that both groups have maintained a presence in the U.S. since the 1980s.
- Swecker claims U.S. authorities 'know that they have cells here' and that there are 'lone sympathizers' within domestic protest movements, while acknowledging these are intelligence assessments rather than newly uncovered plots.
- Swecker links perceived current risk to what he calls 'four years of open borders,' arguing that recent border security vulnerabilities likely enabled additional terrorist infiltrations, although he offers no specific cases.
- The article draws out Jason Pack’s explanation that heightened monitoring around a conflict like Operation Epic Fury is standard practice and that the domestic threat environment can 'shift, potentially significantly' when the U.S. engages adversaries with proxy networks.
- Fox reports that federal and local law enforcement have increased on‑the‑ground security in major U.S. cities while emphasizing that no specific, credible domestic threat has been publicly identified to date.
5:33 PM
Enemy within: Counterterrorism experts fear sleeper cells could be poised inside US
New information:
- Chris Swecker, former FBI assistant director, says that if Hezbollah or Hamas cells in the U.S. were ever going to act violently, "it's now," and asserts both groups have had a U.S. presence since the 1980s.
- Swecker explicitly ties perceived "four years of open borders" to an alleged increased risk that terrorists or sympathizers infiltrated the U.S. and protest movements.
- Jason Pack, a retired FBI supervisory special agent, emphasizes that intelligence and counterterror communities prepare for these scenarios long before conflict and that U.S. military action with Israel can significantly shift the domestic threat environment.
- The piece reiterates that no specific, credible plots have been publicly identified even as FBI counterterror and intelligence units are instructed to be on "high alert" and mobilize assets.
February 28, 2026