Even so, several of the officials said they were not aware of any specific plots in the works.
The military’s secretive Joint Special Operations Command has seized on intelligence gathered over time to strike Hurras al-Din fighters and leaders. On June 30, the military said it carried out an air attack on a training facility near Aleppo province. “This operation targeted AQ-S operatives responsible for plotting external attacks threatening U.S. citizens, our partners, and innocent civilians,” the Pentagon’s Central Command said in a statement, referring to Al Qaeda in Syria.
Then, on Aug. 31, the military said it conducted an airstrike against an Al Qaeda leadership facility north of Idlib. “Northwest Syria remains a safe haven where AQ-S leaders actively coordinate terrorist activities throughout the region and in the West,” the military said in a statement.
The Pentagon publicly does not distinguish between Hurras al-Din and Hayat Tahrir al-Sham, calling them both Al Qaeda in Syria, but American analysts privately say Hurras al-Din poses the larger threat to the West and are the militants being targeted.
The Trump administration has also stepped up diplomatic and intelligence-gathering efforts against Hurras al-Din. This month, the State Department designated Hurras al-Din as a terrorist organization, and offered a reward of up to $5 million each for information on three of the group’s leaders who “have been active in Al Qaeda for years and remain loyal” to Mr. Zawahri.
The State Department and the United Nations have presented descriptions of the three leaders, and the following descriptions are based on those assessments.
Hurras al-Din initially wanted to present a Syrian identity, so a Syrian national, Faruq al-Suri, also known as Samir Hijazi and Abu Hammam al-Shami, was appointed as its overall commander, according to State Department and United Nations assessments. “He fought in Afghanistan in the 1990s,” according to the State Department assessment, “and trained Qaeda fighters in Iraq, among other activities.” Mr. Hijazi had previously been reported killed, but reports differed on when and how he might have died.
A second leader, Abu Abd al-Karim al-Masri, also known as Karim, is an Egyptian national. In 2018, Mr. al-Masri was a member of Hurras al-Din’s leadership team and was a mediator between the group and the Nusra Front.