In addition to a broader campaign of airstrikes against Islamic State targets across Syria on Monday night, the United States also pounded a little-known but well-resourced al-Qaeda cell that some American officials fear could pose a direct threat to the United States.

The Pentagon said in a statement early Tuesday that the United States conducted eight strikes west of Aleppo against the cell, called the Khorasan Group, targeting its “training camps, an explosives and munitions production facility, a communications building and command and control facilities.”

The U.S., along with Arab allies, carried out a series of attacks Tuesday on the Islamic State in Syria. Video posted to social media purports to show the aftermath of those airstrikes. (The Washington Post)

Army Lt. Gen. William C. Mayville Jr., director of operations for the Joint Chiefs of Staff, later told reporters that the group was in the “final stages of plans to execute major attacks against Western targets and potentially the U.S. homeland.” He added, “We believe the Khorasan Group was nearing the execution phase of an attack either in Europe” or the United States, having attempted to recruit Westerners who can more easily enter the target countries.

Mayville said the group was hit by ship-launched Tomahawk cruise missiles during the first of three waves of attacks early Tuesday.

The attacks bring broader attention to the group of clandestine al-Qaeda operatives, which U.S. officials first warned about last week. The group “has established a safe haven in Syria to develop external attacks, construct and test improvised explosive devices and recruit Westerners to conduct operations,” the Pentagon said.

The mission of the Khorasan, led by longtime al-Qaeda leader Muhsin al-Fadhli, appears to be different than other militant groups operating in Syria.

Its objective in Syria isn’t to overthrow Bashar al-Assad, or accumulate land and resources like Islamic State. Rather, its members have come from Pakistan, Yemen and Afghanistan to exploit the flood of Western jihadists who now have skin in the fight — and possess very valuable passports. According to the Associated Press, al-Qaeda leader Ayman al-Zawahiri dispatched the group to recruit those Western fighters, who have a better chance of escaping scrutiny at airports and could place bombs on planes.

James R. Clapper Jr., the director of national intelligence, said late last week that “in terms of threat to the homeland, Khorasan may pose as much of a danger” as the Islamic State. The New York Times then reported that the group posed a “more direct threat” to the United States and Europe than the Islamic State.

“The group’s repeated efforts to conceal explosive devices to destroy aircraft demonstrate its continued pursuits of high-profile attacks against the West, its increasing awareness of Western security procedures and its efforts to adapt to those procedures that we adopt,” Nicholas Rasmussen, deputy director of the National Counterterrorism Center, recently said, referring to al-Qaeda’s bombmaking branch in Yemen.

But beyond such intent, little is known of Khorasan. Even now, it’s unclear how many members Khorasan has, how long it’s been in existence, or what its core message is. Its low profile provides a sharp contrast to the flamboyance of the Islamic State, which operates with an almost pathological desire for attention, publishing graphic-heavy magazines and flooding social media with images of carnage.

What is known of Khorasan barely extends beyond its leader, a notorious al-Qaeda operative whom President George W. Bush mentioned in a 2005 speech. U.S. officials have tracked Fadhli for at least a decade, and he is cited by both the United Nations and the State Department as having participated in al-Qaeda plots. The State Department, calling Fadhli a “senior facilitator and financier,” put out a $7 million reward for information about his location in 2012.

“He has assisted al-Qaeda in moving multiple operatives from Pakistan via Iraq and Turkey to destinations in Europe, North Africa and Syria,” a State Department release said, “and [he] is believed likely to continue moving experienced al-Qaeda operatives to reinforce and gain influence in those areas.”

Fadhli’s rise through the al-Qaeda ranks was both and meteoric and startling. Born on April 24, 1981, in Kuwait, he ascended so quickly that he knew of the Sept. 11 attacks when he was barely 20 and was then tapped for additional responsibilities and terror plots, American officials said. He eventually connected with some of the most notorious terrorists of the past generation, including Abu Musab al-Zarqawi, leader of al-Qaeda in Iraq.

“He was the bodyguard and second-in-command for a leader in the al-Qaeda network and fought for al-Qaeda in the north of Afghanistan,” the United Nations reported. “Al-Fadhli also fought against Russian forces in Chechnya, where he trained in the use of firearms, anticraft guns and explosives. Al-Fadhli was a facilitator connected with the al-Zarqawi groups in Iraq, providing support to fighters there.”

But where he appeared to show his true worth to the group was in his fundraising and organizational skills. He allegedly raised money for an October 2002 attack on a French ship off the coast of Yemen, killing one crew member and disgorging 50,000 barrels of crude oil that inundated 45 miles of coastline. And soon, he had stitched together an “extensive network” of Kuwaiti jihadist donors, according to the State Department.

Following a stint in a Kuwaiti prison for funding terrorist activities, he landed in Iran, where he was soon leading an Iranian al-Qaeda cell, according to the Treasury Department. In that position, he “facilitate[d] the travel of extremists to Afghanistan or Iraq via Iran,” it said. “In addition to providing funding for al-Qaeda activities in Afghanistan and Pakistan, [Fadhli’s] network is working to move fighters and money through Turkey to support al-Qaeda affiliated elements in Syria.”

And now, officials said, he’s trying to do the reverse: Move Western jihadists out of Syria, where Khorasan thrives off chaos. There’s “an unholy mix of people in Iraq and Syria right now,” Rep. Adam Schiff (D-Calif.) of the House Intelligence Committee told AP. “They can combine in ways that could pose a greater threat than their individual pieces. And that’s something we worry about.”

Updated from Monday’s editions at 7:16 a.m. and 1:52 p.m. Tuesday.