Syrian Airstrikes Raise Lone Wolf Terror Threat in US, Feds Warn

PHOTO: The guided-missile cruiser USS Philippine Sea launches a Tomahawk cruise missile at Islamic State group positions in Syria as seen from the aircraft carrier USS George H.W. Bush on the Arabian Gulf, Sept. 23, 2014.Eric Garst/U.S. Navy/AP Photo
The guided-missile cruiser USS Philippine Sea launches a Tomahawk cruise missile at Islamic State group positions in Syria as seen from the aircraft carrier USS George H.W. Bush on the Arabian Gulf, Sept. 23, 2014.

American airstrikes in Syria overnight halted the threat of terrorist attacks in the U.S. homeland from organized groups like ISIS and al Qaeda, but raised the specter of angry lone-wolf sympathizers carrying out an attack on their own, federal authorities said today.

The American airborne offensive could potentially embolden self-radicalized terrorists to strike inside the homeland, the Department of Homeland Security and FBI say in a joint bulletin issued to local, state and federal law enforcement late today.

While “single events generally do not provoke an immediate response” from homegrown extremists, “[W]e believe these strikes will contribute to homegrown violent extremists’ … broader grievances about U.S. military intervention in predominantly Muslim lands, possibly motivating Homeland attacks,” according to the bulletin.

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Less likely in the near-term, the bulletin says, is an attack “in direct response to the strikes in Syria” by organized terrorist groups, including core Al Qaeda or the Islamic State of Iraq and Syria (ISIS), the brutal terrorist group that has seized vast swaths of territory in Syria and neighboring Iraq and was a target of the airstrikes overnight.

The bulletin notes ISIS’ prolific online campaign and cites a recent audio message from ISIS that called for “lone offender attacks in the Homeland in retaliation for U.S. military operations in Iraq and Syria,” as the bulletin put it.

And though “in the near term” most homegrown terrorists will try to join groups overseas rather than carry out their own attacks in the United States, authorities “cannot rule out the possibility … that some [homegrown terrorists], acting alone or in small groups, could attempt simple attacks with little or no warning,” according to the bulletin.

The bulletin stresses the “importance” of the American public reporting suspicious behavior and “remain[ing] vigilant.”

“We face an increased challenge in detecting terrorist plots underway by individuals or small groups acting quickly and independently or with only tenuous ties to foreign handlers,” the bulletin reads. “Pre-operational indicators are likely to be difficult to detect.”

Still, the bulletin offers law enforcement “potential indications” that someone in the United States might be seeking to retaliate for the airstrikes, including “new or increased advocacy of violence” and “adoption of new lifestyles, changes in appearance, and segregation from normal peer and family groups in association with advocating criminal or terrorist activity.”

Another group targeted by the airstrikes is known as the Khorasan group, a little-known collection of “seasoned Al Qaeda operatives” that was “nearing the execution phase for an attack in Europe or the homeland,” U.S. officials said today. And only hours later, the bulletin says the airstrikes “may have temporarily disrupted attack plotting against U.S. and Western interests” by both ISIS and the Khorasan group.

The planned attack against the West pushed the United States to strike the Khorasan Group in Syria and is linked to the same threat ABC News first disclosed this summer.

ABC News reported earlier this year that U.S. officials learned that a particularly extreme “subset” of terrorist groups in Syria was working alongside operatives from al Qaeda’s prolific offshoot in Yemen to produce “creative” new designs for bombs packed into electronic devices like cell phones or laptops, sources said. The officials did not identify the group at the time.

Specifically, associates of the al Qaeda affiliate in Syria — the al Nusra Front — and radicals from other groups were teaming up with elements of the Yemen-based group Al Qaeda in the Arabian Peninsula (AQAP) to potentially down a plane bound for the U.S. or Europe with help from one of the thousands of Americans and other foreign fighters carrying U.S. and European passports who have joined extremist groups in the region.

The group – comprised of operatives from Yemen, Afghanistan, Iraq, Chechnya and elsewhere -- had found a “safe haven” in Syria where they were able to “construct and test improvised explosive devices,” senior U.S. officials said today. The joint effort with AQAP, which built such innovative devices as the “underwear bomb” that ultimately failed to detonate in a plane over Detroit on Christmas Day 2009, made the threat out of Syria “more frightening than anything” else the Obama administration had seen, Attorney General Eric Holder told ABC News in July.

The threat prompted airports overseas to increase security measures that month.

More than 12,000 foreign fighters, including more than 100 Americans, have now joined tens of thousands of other fighters operating in Syria and neighboring Iraq, where ISIS is now wreaking havoc and recruiting more Westerners to fight.

The bulletin today comes one month after DHS and FBI issued a similar bulletin to law enforcement, urging them to be alert for possible attacks in retaliation for U.S. airstrikes against ISIS at the time. Such bulletins outlining potential concerns from U.S. officials and urging increased vigilance are common – essentially acting as a generic “FYI” to local, state and federal law enforcement who don’t have the same access to classified information that the nation’s top counterterrorism officials see every day.