WASHINGTON — Airstrikes in Syria against the extremist Khorosan group were prompted by planning for an ‘‘imminent’’ terror attack on US soil, the Pentagon said Tuesday.
‘‘We believe the individuals plotting and planning it were eliminated’’ in the eight US airstrikes overnight, Rear Adm. John Kirby, the Pentagon spokesman, said in an interview with ABC’s ‘‘Good Morning America’’ program.
Amid attention on the threat from Islamic State in Iraq and Syria, Khorasan has emerged in recent weeks as a more immediate peril in the view of the US intelligence community because it’s more focused on attacking America and Europe.
The militant group is made up of a ‘‘network of seasoned Al Qaeda veterans’’ preparing to attack ‘‘United States and Western interests,’’ the Defense Department said in a statement. US officials so far have provided no details about the terrorists’ planned attack or the credibility of the intelligence they had on it.
Khorosan’s intentions put ‘‘them at the top of groups threatening the West,’’ said Seth Jones, director of the International Security and Defense Policy Center at the Rand Corp., a policy group based in Santa Monica, California.
Groups such as Al Qaeda in the Arabian Peninsula, based in Yemen, and the al-Nusra Front, a Syrian-based Al Qaeda affiliate, also pose a grave danger to the US and European allies and are actively plotting, Jones said.
The strikes against Khorosan militants west of Aleppo were conducted by the US using Tomahawk missiles, according to the Pentagon. They were waged separately from a series of strikes on 14 Islamic State targets in Syria by the US and five Arab nations.
A chief concern about the Khorosan faction is the group’s evident link to Al Qaeda in the Arabian Peninsula’s leading bomb designer in Yemen, Ibrahim al-Asiri, whom the United States has targeted with drones, so far without success. His specialty is said to be bombs designed into clothing and implanted in the human body.
‘‘It must be clear to anyone who would plot against America and try to do Americans harm that we will not tolerate safe havens for terrorists who threaten our people,’’ President Barack Obama said today at the White House, before leaving for New York and events at the United Nations General Assembly.
Lt. Gen. William Mayville, director of operations for the Joint Chiefs of Staff, was cautious in his evaluation, saying he didn’t know yet whether the strikes against Khorosan were successful or whether any of the group’s leaders were killed.
‘‘We’re still assessing the effects of our strikes,’’ Mayville said at a Pentagon press conference Tuesday. The US believed the group ‘‘was nearing the execution phase of an attack either in Europe or the homeland’’ and ‘‘has attempted to recruit Westerners to serve as operatives or to infiltrate back into their homelands,’’ he said.
Despite the ‘‘bluster’’ of Islamic State, the main focus of US policy makers in recent weeks, Jones said the Al Qaeda breakaway group poses less of a threat because ‘‘Islamic State’s focus right now seems to me to be trying to keep control of the territory it has in Syria and expand what it has in Iraq.’’
Khorosan ‘‘is essentially Al Qaeda central moving into the Syria conflict,’’ said Peter Bergen, a national security analyst and member of the Bipartisan Policy Center’s Homeland Security Project, who spoke at a forum today on terrorism.
US officials had warned in the past week that despite the focus on Islamic State, the intelligence community needs to continue watching less high-profile terrorists.
‘‘What we can’t do is let down our guards for any one of these’’ groups, CIA Director John Brennan said at a Sept. 17 conference on intelligence issues in Washington. ‘‘You have to be looking at some of these smaller groups.’’
Those include the al-Nusra Front, which has ties to Al Qaeda and has made clear its intent to launch attacks outside of the Syrian battleground. Speaking at the same conference, James Clapper, director of US National Intelligence, said the Khorosan Group, part of al-Nusra, represents a threat on par with Islamic State. The Khorosan group is also part of the core Al Qaeda that operates along Pakistan’s border with Afghanistan.
Compared with Islamic State, fighters for al-Nusra keep a lower profile on the Internet, with most videos aimed at local Muslims, according to the Mapping Militant Organizations project at Stanford University in California. The videos or postings generally don’t show identifiable fighters from the US and Europe, even though the group attracts the second-largest contingent of foreign militants in Syria.
The core group was dispatched from the tribal areas of Pakistan to recruit European Union and US passport holders coming to Syria to wage jihad, and some US intelligence officials think it also may be recruiting in Libya and Somalia, also magnets for young, disaffected Muslims.